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Behavior  Monographs 


Volume  2,  Number  3,  1913  Serial  Number  8 

Edited  by  JOHN  B.  WATSON 

The  Johns  Hopkins  University 


Audition  and  Habit  Formation 
in  the  Dog 

HARRY  MILES  JOHNSON 

Dissertation  submitted  to  the  Board  of  University  Studies  of  the 
Johns  Hopkins  University  in  conformity  with  the  require- 
ments for  the  degree  of  Doctor  of  Philosophy 


Published 

at  Cambridge,  Boston,  Mass. 

HENRY  HOLT  & COMPANY 
34  West  33d  Street,  New  York 
(jr.  E.  STECHERT  & CO.,  London,  Paris  and  Leipzig,  Foreign  Agents 


“l"VamroFIUJ''°xuamr 

10 191? 

Behavior  Monographs 


Volume  2,  Number  3,  1913 


Serial  Number  8 


Edited  by  JOHN  B.  WATSON 

The  Johns  Hopkins  University 


Audition  and  Habit  Formation 
in  the  Dog 


HARRY  MILES  JOHNSON 

If 


Dissertation  submitted  to  the  Board  of  University  Studies  of  the 
Johns  Hopkins  University  in  conformity  with  the  require- 
ments for  the  degree  of  Doctor  of  Philosophy 


Published 

at  Cambridge,  Boston,  Mass. 

HENRY  HOLT  & COMPANY 
34  West  33d  Street,  New  York 
G.  E.  STECHERT  & CO.,  London,  Paris  and  Leipzig,  Foreign  Agents 


<3  S>  ^ 


CONTENTS  Page 

Acknowledgment iv 


Part  I.  Pitch-Discrimination 

Historical 1-19 

Method  of  Pavloff’s  school 1 

Goltz’s  “ Gehirnlos  Hund  ” 3 

Munk’s  experiments * 3 

Kalischer’s  earlier  work 4 

Rothmann’s  experiments 13 

Kalischer’s  later  work 15 

Swift’s  experiment 18  , 

Summary 19 

Preliminary  experimentation 19-27 

Problem,  animals  and  method 19 

Results 24 

Control  experiment 27 

Conditions  of  reliable  experimentation 30 

Further  experiments  on  pitch-discrimination 41 

Experiments  on  discrimination  between  noises 46 

Summary 51 

Part  II.  Habit-Formation 

Problem 54 

Apparatus 54 

Animals 55 

Method  of  training 57 

Results . .. 59 

Operative  proceeding 71 

Post-operative  tests 71 

Retention 74 

Control  tests 74 

Summary 78 


iii 


Aaa\*  0*  Can  y 


ACKNOWLEDGMENT 

The  experiments  herein  described  were  carried  on  under  the 
general  direction  of  Professor  John  B.  Watson  of  the  Johns 
Hopkins  University,  who  has  been  unsparing  in  suggestion, 
assistance  and  criticism.  Professor  Knight  Dunlap  has  ren- 
dered valuable  criticism  as  to  method  and  apparatus.  Dr. 
Adolf  Meyer  furnished  the  two  animals  used  throughout  the 
experiments  in  audition  and  in  a part  of  the  work  described 
in  part  two.  Professors  Angell  and  Carr  placed  the  facilities  of 
the  laboratory  of  the  University  of  Chicago  at  my  disposal  in 
the  summer  of  1911,  at  no  small  inconvenience  to  themselves. 
Dr.  Walter  E.  Dandy,  Dr.  Conrad  Jacobson  and  Dr.  Henry 
Dick  very  kindly  performed  some  necessary  operations  and 
furnished  other  aid. 


iv 


I.  PITCH-DISCRIMINATION1 


HISTORICAL 

Several  reports  of  experimental  tests  on  the  audition  of  the 
dog  have  been  published.  Most  of  them  have  been  made  by 
physiologists,  who  were  interested  not  so  much  in  the  degree  of 
the  animal’s  discrimination  as  in  the  localization  of  the  cerebral 
centers  which  govern  it. 

Pavloff ’s 2 school  (notably  Selionyi 3)  have  attempted  the  de- 
termination of  the  dog’s  sensitivity  to  differences  of  pitch, 
by  the  saliva-reflex  method.  Yerkes  and  Morgulis 4 have 
given  a comprehensive  description  in  English  of  this  method. 
Some  of  the  most  important  points  in  their  article  are  set  forth 
below. 

The  saliva-reflex  (secretion  of  saliva)  occurs  under  two  strik- 
ingly different  conditions:  when  the  glands  are  stimulated  by 
the  specific  (chemical)  stimuli  for  secretion;  and  when  the 
animal  is  presented  with  visual,  olfactory,  auditory  or  other 
stimuli,  which  have  been  concomitants  of  direct  stimuli  of  the 
salivary  grands.  “The  environment  of  the  dog  may  be  said  to 
consist  of  two  sets  of  properties,  the  essential  and  non-essen- 
tial.” Properties  essential  for  a given  reaction  are  those  char- 
acteristics of  an  object  which  “regularly  and  definitely  determine 
the  reaction  of  the  organism;”  non-essential  properties  of  the 
object  are  “ those  which  only  in  a highly  variable  and  inconstant 
manner  condition  the  reaction.”  The  chemical  property  of  food, 
whereby  it  acts  on  the  receptors  of  the  mouth  of  the  dog,  is  an 
example  of  the  essential  class;  the  brightness,  color,  etc.,  are 
examples  of  the  non-essential  properties.  Reflex  responses  to 
“essential”  properties  are  called  “unconditioned”  reflexes; 

1 From  the  psychological  laboratory  of  the  Johns  Hopkins  University. 

2 PAVLoff,  J.  P.  The  scientific  investigation  of  the  psychical  faculties  or 
processes  in  the  higher  animals.  Lancet,  1906,  pp.  911-915.. 

3 Selionyi,  G.  P.  Contribution  to  the  study  of  the  reactions  of  the  dog  to 
auditory  stimuli.  Dissertation.  St.  Petersburg,  1907.  (In  Russian.)  Method 
reported  by  Yerkes  and  Morgulis,  l.c.,  below. 

4 Yerkes,  R.  M.  and  Morgulis,  S.  The  method  of  Pavloff  in  -comparative 
psychology.  Psychological  Bulletin,  1909,  pp.  257  ff. 


2 


HARRY  MILES  JOHNSON 


those  in  response  to  “non-essential”  properties  are  called  “con- 
ditioned” reflexes. 

The  following  experimental  procedure  is  followed:  “A  nor- 
mally active  and  healthy  dog  of  vigorous  salivary  reaction 
having  been  selected,  the  duct  of  one  of  the  salivary  glands — 
the  parotid  for  example — is  exposed  on  the  outer  surface  of  the 
cheek  and  a salivary  fistula  is  formed.  The  wound  heals  com- 
pletely within  a few  days  and  the  dog  exhibits  no  signs  of  dis- 
comfort or  inconvenience.  Those  who  have  used  the  method 
insist,  indeed,  that  their  animals  are  perfectly  normal.”  Devices 
are  applied  to  catch  and  measure  the  saliva  secreted  in  different 
intervals  of  time. 

In  the  auditory  tests  the  animal  is  accustomed  to  being  fed 
at  a certain  tone  or  sound  until  the  saliva  secretion  begins  when 
the  sound  is  made.  Unfamiliar  sounds  do  not  provoke  the  reac- 
tion. Selionyi  reports  that  discrimination  was  established  by 
this  method  between  tones  only  a quarter  of  a tone  different  in 
pitch.  Further  difference -diminution  than  this  did  not  produce 
such  marked  difference  in  secretion:  if  the  two  tones  were  very 
near  together  in  pitch,  the  “unfamiliar”  one  provoked  a secre- 
tory response,  but  not  to  such  a degree  of  intensity  as  did  the 
“familiar”  one.  If  the  “familiar”  tone  was  sounded  too  faintly, 
however,  the  reflex  conditioned  by  it  was  either  very  weak  or 
else  did  not  appear.  If  an  unfamiliar  tone  the  pitch  of  which 
differed  very  slightly  from  that  of  the  familiar  tone  were  given 
just  before  the  familiar  one  was  sounded,  the  reflex  condi- 
tioned by  the  latter  was  partially  inhibited. 

Yerkes  has  remarked  that  there  are  several  obvious  disad- 
vantages attached  to  this  method:  “conditioned  reflexes”  die 
out  with  repeated  stimulation;  the  quality  of  food  given  con- 
ditions a remarkable  variation  in  the  flow;  and  the  rate  of 
secretion  is  conditioned  also  by  the  time-interval  between  stim- 
uli. To  this  I would  add  the  suggestion  that  there  may  be  also 
a tendency  to  rhythmical  change  in  the  rate  and  quantity  of 
secretion.  Moreover,  Selionyi  tells  us  that  the  animal  was 
affected  by  the  “kind  of  movements”-  made  by  the  experi- 
menter, who  had  to  be  careful  neither  to  move  too  quickly  nor 
to  hold  himself  too  rigidly  quiet.  As  slight  changes  of  posture 
are  very  often  involuntary  there  is  room  for  doubt  whether  they 


HABIT  FORMATION  IN  THE  DOG 


3 


were  eliminated.  That  the  method  itself  can  be  put  to  prac- 
tical use  and  be  so  improved  as  to  become  wholly  reliable 
has  not  yet  been  demonstrated.  In  any  case  there  remains  the 
question  whether  the  results  obtained  by  this  method  would 
show  the  relative  importance  of  the  animal’s  sensitivity  to 
given  stimuli,  as  referred  to  his  behavior  under  normal  condi- 
tions. A change  in  the  auditory  stimulus  great  enough  to  occa- 
sion change  in  the  saliva-reflex  conditioned  by  it  may  be  much 
too  slight  to  occasion  a change  in  the  so-called  voluntary  reac- 
tions; or  the  contrary  may  be  true. 

In  1891,  Goltz5  removed  the  entire  cerebrum  from  one 
dog,  which  lived  for  over  eighteen  .months  thereafter  under 
constant  observation  in  the  laboratory.  At  very  high  tones  or 
at  very  loud  noises  the  animal  would  prick  its  ears  or  turn  its 
head.  If  the  stimulus  was  very  intense  it  would  even  strike  at 
its  ear  with  the  forefoot  “as  if  it  wished  to  stop  its  ear.”  From 
these  reactions,  Goltz  denied  that  the  animal  was  “totally 
deaf.”  Munk  calls  attention  to  the  possibility  that  the  animal 
was  reacting  to  pain -stimuli  and  not  to  tone  or  even  to  noise. 
This  suspicion  seems  to  be  well  grounded. 

Munk6  himself  made  some  experiments  with  dogs,  using 
nine  pipe-organ  tones  about  an  octave  apart,  and  taking  the 
animals’  ear-,  head-  and  body-movements  as  criteria  of  audi- 
tion. If  these  movements  were  no  longer  made  after  operation 
on  the  cerebrum,  he  assumed  that  deafness  has  been  produced. 
Having  extirpated  different  regions  of  the  supposed  auditory 
center  from  trained  dogs,  and  having  compared  the  motor  reac- 
tions following  the  operation  with  the  former  responses  of  the 
dogs,  Munk  concluded  that  the  dog’s  center  for  tone  lies  in  the 
temporal  lobe ; that  perception  of  the  high  tones  is  conditioned 
by  the  function  of  the  anterior  portion  of  the  center,  while  that 
of  the  deeper  tones  depends  on  the  activity  of  the  posterior 
region.  While  these  results  are  extremely  interesting,  and  val- 
uable if  it  can  be  established  that  the  animals  reacted  only  to 
auditory  stimuli,  yet  the  behavior  method  is  open  to  the  criti- 
cism that  it  cannot  be  used  to  determine  the  animal’s  discrim, 
ination  between  stimuli.  Kalis cher,  whose  work  we  shall  pres. 

5 Described  by  Munk,  H.  Functionen  von  Hirn  und  Riickenmark.  Berlin, 
1909.  Article  Ueber  den  Hund  ohne  Grosshirn.  1894.  Pp.  137  ff. 

6 Munk,  H.  Ueber  die  Functionen  der  Grosshirnrinde.  Berlin,  1890.  Pp. 
113  ff. 


4 


HARRY  MILES  JOHNSON 


ently  take  up,  asserts  also  that  dogs  which  after  operation  made 
no  such  responses  as  Munk  chose  as  criteria,  could  yet  discrim- 
inate accurately  between  tones  and  between  chords.  Assuming 
that  Kalischer ’s  dogs  were  reacting  only  to  auditory  stimuli — 
of  which  fact  there  is  room  for  doubt — this  objection  to  Munk’s 
method  would  be  fatal. 

Kalischer7  reported  in  February,  1907,  some  experiments 
which  he  had  carried  on  for  the  purpose  of  testing  the  relation 
between  the  temporal  cortex  and  tone -perception.  He  purposed 
particularly  to  test  experimentally  the  conclusion  of  Munk  re- 
garding the  specialized  function  of  this  area. 

The  number  and  ages  of  the  animals  used  is  not  reported,  but 
they  were  chosen  from  at  least  six  different  breeds.  Kalischer 
trained  his  dogs  to  take  food  upon  the  sounding  of  a given  tone 
and  to  refrain  from  seizing  it  upon  the  sounding  of  any  other. 
The  food  was  either  held  in  the  experimenter’s  hand  before  the 
dog  or  laid  on  a chair  by  which  the  experimenter  stood. 

The  tones  were  sounded  first  on  the  organ  used  by  Munk, 
which  contained  nine  pipes — the  octaves  from  Cx  to  c7.  Later 
he  substituted  the  piano  and  still  later  the  harmonium,  finding 
the  latter  best  suited  to  his  purposes. 

The  daily  tests  on  each  animal  were  arranged  about  as  fol- 
lows : Kalischer  struck  a certain  tone  and  as  long  as  it  sounded 
fed  the  animal  bits  of  meat  from  the  hand.  In  the  first  two 
daily  experiments  he  sounded  only  the  one  food-tone,  so  that 
he  might  accustom  the  animal  to  being  fed  at  the  sound.  “ From 
about  the  third  day  on,”  he  says,  “I  struck  now  and  then 
another  tone,  and  while  it  sounded  I held  the  bit  of  meat  in  the 
closed  hand,  so  that  the  animal  could  not  reach  it  and  had  to 
content  himself  with  sniffing  at  my  hand.”  Then  he  caused  the 
food-tone  to  sound  again  and  fed  the  animal  bits  of  meat,  one 
after  the  other  as  long  as  the  sound  lasted.  In  all  his  tests 
thereafter,  he  “struck  besides  the  food-tone  other  ‘Gegentone’ 
and  at  the  latter  prevented  the  animal  from  seizing  the  food.” 

Kalischer  does  not  say  in  what  order  the  respective  stimuli 
were  given.  The  expression  “now  and  then  (zwischendurch) ” 
is  far  less  definite  than  one  should  desire  or  expect.  As  previous 

7 Kalischer,  Otto.  Zur  Function  der  Schlaeffenlappens  des  TGrosshirns. 
Eine  neue  Horprufungsmethode  bei  Hunden;  zugleich  ein  Beitrag  zur  Dressur 
als  physiologischer  Untersuchungsmethode.  Sitz.  der  K.  Preuss.  Akad.  d.  TFis- 
schftn.  1907,  pp.  204  ff. 


HABIT  FORMATION  IN  THE  DOG 


5 


experimenters8  have  pointed  out,  and  as  appears  in  the  behavior 
of  every  animal  which  I have  used  in  discrimination  tests,  the 
animals  quickly  form  the  habit  of  reacting  in  a certain  rhvthm 
or  in  a regular  order  or  by  taking  a certain  position,  regardless 
of  the  stimulus  presented.  These  “ position  habits  ” and  rhythmic 
choices  are  exceedingly  hard  to  break  up.  If  the  order  of  pre- 
sentation of  the  stimuli  happens  to  coincide  with  or  approx- 
imate the  habitual  order  adopted  by  the  animal,  a very  high 
record,  or  one  even  of  perfect  accuracy  may  be  obtained  when 
the  animal  really  has  not  been  affected  by  the  stimulus.9  And 
indeed  nothing  is  easier  than  for  the  experimenter  to  fall  into  a 
rhythmic  order  of  presenting  the  stimuli  unless  he  determines 
beforehand  a chance  order  of  presentation  for  each  day’s  series 
of  trials.  This  question  should  be  borne  in  mind  while  Kalischer’s 
results  are  being  considered,  for  we  shall  have  occasion  to  con- 
sider it  later. 

A further  criticism  may  be  made  at  this  point.  Kalischer 
writes  that  the  harmonium  suited  his  purposes  better  than  the 
piano  and  some  other  instruments,  because  with  the  harmonium 
it  is  possible  to  sustain  the  tone  as  long  as  is  desired — or  until 
the  animal  has  reacted.  Now,  it  should  not  be  forgotten  that 
the  duration  of  the  stimulus  may  easily  become  the  basis  of  the 
animal’s  choice.  In  such  an  experiment  as  Kalischer’s,  when 
the  dog  is  to  react  to  one  tone  and  is  under  penalty  to  inhibit 
reaction  to  the  others,  reaction  may  not  occur  immediately  fol- 
lowing the  stimulus.  If  the  animal  is  timid  reaction  will  prob- 
ably be  delayed.  There  is  a strong  temptation,  which  I have 
experienced,  to  sustain  the  stimulus-tone  a little  longer  if  the 
animal  does  not  react  properly  or  promptly,  so  as  to  give  him 
full  opportunity  to  hear  the  tone.  On  the  other  hand  the  ex- 
perimenter is  likely  to  become  content  quickly  if  the  animal 
does  not  react  immediately  to  a “Gegenton”  and  damp  the 
stimulus;  whereas  the  animal  might  have  reacted  had  the  tone 
been  held  a little  longer.  Rothmann,  whose  work  we  shall 
presently  discuss 10  tells  us  that  in  his  experiments  the  dura- 
tion of  the  stimulus-tone  was  a disturbing  factor,  although  he 

8 c.  f.,  Yerkes,  R.  M.  The  Dancing  Mouse,  p.  111. 

9 An  actual  record  of  one  of  my  animals,  nicely  illustrating  this  point  is  shown 
on  page  52. 

10  Rothmann,  Max.  Ueber  die  Ergebnisse  der  Horprufung  an  dressierten 
Hunden.  Arch.  f.  Physiol.,  1908,  pp.  103  ff. 


6 


HARRY  MILES  JOHNSON 


reports  no  precautions  against  it,  and  does  not  consider  it  in 
interpreting  his  data.  He  says:  “After  three  weeks  (of  train- 
ing) the  dogs  reacted  with  perfect  accuracy;  only  now  and 
then,  at  a tone  of  abnormally  long  duration,  a false  reaction 
occurred.”  11  Again,  speaking  of  animals  bereft  of  one  posterior 
corpus  quadrigeminum,  which  were  hardly  disturbed  by  the 
operation : “If  the  tones  were  sounded  for  a somewhat  longer 
time,  then  the  dogs  came  at  every  tone.”  12  To  guard  against 
disturbance  from  this  source,  care  should  be  taken  to  make  the 
duration  of  all  stimuli  the  same  at  every  presentation.  Before 
Kalischer  and  Rothmann  assumed  that  their  animals  were  dis- 
criminating only  the  pitch  of  tones,  they  ought  to  have  shown 
in  control  tests  that  their  animals  would  not  react  to  a “ Gegen- 
ton”  no  matter  how  long  was  its  duration.13 

Kalischer  does  not  tell  us  how  many  trials  he  gave  the  animals 
at  each  daily  test,  nor  how  many  trials  altogether  were  required 
to  achieve  perfection.  Data  on  both  of  these  questions  are 
highly  desirable  in  reports  of  behavior  experiments.  He  does 
say  in  this  report,  however,  that  the  daily  test  on  each  animal 
lasted  not  longer  than  five  or  six  minutes.  In  reporting  another 
experiment  of  similar  character  he  tells  us  that  about  fifteen 
minutes  were  required  to  give  eight  to  ten  trials 14.  This 
tallies  with  the  writer’s  experience.  An  animal  should  not  be 
worked  much  faster  than  this,  as  the  risk  of  its  becoming  “in- 
attentive” is  too  great.  But  it  is  evident  that  the  stimulus 
cannot  be  presented  over  three  to  five  times  in  the  five  or  six 
minutes  which  Kalischer  allowed  for  a daily  series.  The  possi- 
bility of  varying  the  order  of  presentation  of  food-tone  and 
“Gegentone”  is  also  greatly  limited  by  the  brevity  of  the  series. 
For  this  reason  it  is  doubtful  whether  the  animal  is  given  a 
fair  test  of  discrimination.  An  animal  making  random  choices 
only  may  chance  to  make  most  of  the  first  three  or  four  of  a 
series  correctly,  and  yet  be  unable  to  maintain  accuracy  through 
a varied  series  of  ten  to  twenty  trials.  On  the  other  hand,  some 

11  Loc.  cit.,  p.  107. 

12  Loc.  cit.,  p.  109. 

13  It  may  be  said  here  that  it  is  quite  possible  to  make  tests  of  the  dog’s  sensi- 
tivity to  mere  duration-difference  of  auditory  stimuli.  The  results  of  such  an 
investigation  should  prove  very  interesting. 

14  Kalischer,  Otto.  Weitere  Mitteilung  ueber  die  Ergebnisse  der  Dressur 
als  physiologischer  Untersuchungsmethode  auf  den  Gebieten  des  Gehor — Geruchs- 
und  Farbensinns.  Arch.  f.  Physiol.,  1909. 


HABIT  FORMATION  IN  THE  DOG 


7 


of  my  animals,  after  making  three  or  four  wrong  choices  succes- 
sively have  finished  a series  of  fifteen  trials  correctly. 

To  return  to  Kalischer’s  procedure:  He  says,  “From  the 
fifth  or  sixth  day  on,  even  if  I held  the  bit  of  meat  in  the  open 
hand,  many  animals  would  no  longer  attempt  to  seize  it  at  the 
‘ Ge  gent  one.’  Thus  ever  more  frequently  correct  reactions  en- 
sued.” From  this  point  on  the  animals  were  “punished  by  a 
light  blow  on  the  jaw  when  they  snapped  falsely  after  the  food.” 

Some  of  the  animals  were  taught  to  take  food  at  high  tones 
— ome  at  c-2048  d.v. — and  others  at  as  low  tones  as  “C7.”15 
The  “ Gegentone  ” chosen  at  first  were  those  lying  as  far  as 
possible  from  the  food-tone.  After  the  animals  had  learned  to 
inhibit  reaction  to  these,  others  nearer  the  food-tone  were  chosen. 
Kalischer  says  that  the  greater  the  difference  between  food-tone 
and  “Gegenton”  the  more  quickly  the  animal  learned  to  dis- 
criminate ; but  that  it  was  possible  and  not  very  difficult  to 
train  the  animal  to  discriminate  between  the  food-tone  and  one 
only  a semi-tone  removed.  We  should  exarciine  with  some  care 
his  description  of  the  animals’  behavior  in  the  experimental 
situation,  however.  “ Bei  den  weitab  vom  Fresston  liegenden 
Tonen  pflegte  spater  der  gut  dressierte  Hund,  scheinbar  er- 
schreckt,  schnell  zuriickzuspringen,  wahrend  er  bei  den  naher 
leigenden  Gegentonen  offer  Neigung  zeigte,  zuzuschnappen , (italics 
mine)  was  sich  deutlich  an  den  Kopfbewegungen  beobachten 
liess.”  Again:  “Liess  man  den  Fresston  oft  hintereinander 
ertonen,  die  zunachst  prompt  nach  die  Fleischstiicken  gegriffen 
hatten,  Ermudungserscheinen  geltend. ” “Die  Tiere 
horten  auf,  nach  den  Fleischstiicken  zu  greifen;  und  erst  wenn 
man  zwischendurch  wieder  einen  der  Gegentone  angeschlagen 
hatte,  griff en  die  Tiere  von  neuem  beim  Fresston  wieder  in 
gewohnter  Weise  zu.  * * * Auch  hier  war  es  von  Zeit  zu 

Zeit  notig,  zwischendurch  einen  der  Gegentonen  erklingen  zu 
lassen.” 

These  remarks  indicate  that  Kalischer  regarded  his  animals 
as  discriminating  even  though  they  sometimes , did  not  react  to 
the  food-tone  and  did  not  inhibit  reaction  to  “Gegentone.” 
We  may  then  seriously  inquire  what  was  the  experimenter’s 
criterion  of  discrimination.  How  could  he  know  that  failure 
to  respond  was  due  to  fatigue  and  is  not  rather  evidence  of  lack 


15  This  is  doubtless  a misprint:  Ci,  64  d.v.,  is  probably  meant. 


8 


HARRY  MILES  JOHNSON 


of  discrimination?  If  the  reactions  and  inhibitions  are  no  more 
definite  than  this,  interpretation  of  results  is  extremely  unsafe. 
I have  already  referred  to  a day’s  record  made  by  one  of  my 
animals,  showing  an  “accuracy”  of  80%,  whereas-  the  animal 
was  not  being  affected  by  the  stimulus.  Dependable  results 
cannot  be  had  from  less  than  several  fairly  long  and  perfect 
consecutive  daily  records,  obtained  under  conditions  of  control. 

A further  question:  Assuming  that  the  “mental”  condition 
indicated  by  “scheinbar  erschreckt”  was  legitimately  ascribed 
to  the  animals,  to  what  may  we  best  consider  it  due?  Since 
the  experimenter  was  in  the  room,  near  the  dogs,  we  are  not 
safe  in  saying  that  their  “fright”  was  occasioned  by  association 
of  only  the  perceived  tone  with  punishment.  The  work  done 
by  Moll  16  and  later  by  Pfungst  17  and  Stumpf  on  the  now 
famous  horse  of  Herr  v.  Osten,  “ Der  kluge  Hans ,”  showed  that 
in  a situation  of  expectant  interest  it  is  almost  impossible  for 
one  to  avoid  making  certain  slight,  often  unconscious  and  in- 
voluntary movements ; and  it  has  been  demonstrated  that 
animals,  hypnotic  subjects,  gamblers,  mediums,  and  even  the 
most  honest  laboratory  subjects  may  react  unconsciously  to 
such  movements,  thus  accomplishing  the  deception  of  the  ex- 
perimenter and  sometimes  of  themselves.  It  is  not  proof  of 
actual  inhibition  of  such  movements  to  say  as  did  Shepherd  18 
that  “care  was  taken  to  avoid  them.”  The  most  important 
point  brought  out  in  the  investigation  of  Hans  is  that  the  move- 
ments are  made  both  unconsciously  and  involuntarily,  and  are 
usually  discovered  indirectly.  In  Kalischer’s  work  there  is  good 
reason  (especially  in  view  of  the  remarkable  results  reported) 
for  suspecting  the  presence  of  such  a factor.  The  experimenter 
stood  before  the  dog,  being  doubtless  the  center  of  the  animal’s 
interest,  ready  to  give  food  or  to  strike  as  soon  as  the  dog  sprang 
up  on  to  the  chair.  The  punishment  had  to  be  administered 
quickly  to  prevent  the  animal  from  obtaining  the  food.  One 
would  expect  that  slight,  nascent  movements  involved  in  giving 
food  or  striking  would  inevitably  be  made.  Besides  these  and 

16  Moll,  A.  Hypnotism  (4th  ed.) ; tr.  by  Arthur  F.  Hopkirk.  New  York, 
Scribners,  1910. 

17  Pfungst,  Oskar.  Clever  Hans.  Tr.  by  Carl  L.  Rahn.  New  York,  Henry 
Holt  & Company,  1911. 

18  Shepherd,  W.  T.  Discrimination  of  articulate  sounds  by  cats.  American 
Journal  of  Psychology , 1912. 


HABIT  FORMATION  IN  THE  DOG 


9 


other  possible  changes  of  posture  (e.g.,  strain  and  relaxation  of 
neck-  or  body-muscles),  are  possible  involuntary  changes  in 
breathing,  etc.,  any  of  which  the  animal  could  quickly  learn  to 
associate  with  food  or  with  punishment. 

Kalischer  indeed  attempted  two  control-tests  of  the  existence 
of  secondary  criteria.  First,  he  asserts  that  he  made  “some” 
of  his  dogs  temporarily  blind,  by  sewing  their  eyelids  together. 
He  reports  that  the  accuracy  of  discrimination  was  not  affected. 
Now,  if  this  temporary  blindness  were  complete,  this  result  in- 
deed would  show  that  the  secondary  cues  if  there  had  been  any, 
were  not  visual  cues;  but  it  would  not  show  that  there  were 
no  secondary  cues  of  another  kind.  Changes  of  tension  in  the 
operator’s  body-muscles,  of  breathing,  etc.,  can  be  detected  by 
other  than  visual  avenues.  I lay  what  may  seem  undue  stress 
on  this  possibility,  because,  as  will  appear  later,  there  is  reason 
to  believe  that  such  cues,  involuntarily  given,  were  factors  in 
some  tone-discrimination  tests  which  I made  on  blind  dogs. 

Besides  this  form  of  control,  Kalischer  destroyed  one  cochlea 
in  some  other  “well-trained  dogs.”  No  disturbance  is  reported. 
When  the  other  cochlea  was  destroyed,  all  discrimination  ceased. 
Dogs  subjected  to  extirpation  of  both  cochlea  before  any  train- 
ing was  attempted  did  not  learn  to  discriminate  at  all.  Kal- 
ischer regards  this  as  evidence  that  the  other  dogs  had  ignored 
extra -auditory  stimuli.  The  possibility  still  remains,  however, 
that  in  the  tests  given  the  normal  animals,  the  experimenter 
expected  them  to  react  when  the  food-tone  was  sounded,  and  to 
inhibit  reaction  when  other  tones  were  sounded;  and  that  he 
made  “unconscious”  movements  corresponding  to  his  expecta- 
tion, to  which  the  animals  reacted.  On  the  other  hand,  in  test- 
ing dogs  in  which  the  cochlea  had  been  destroyed,  it  is  possible 
that  the  experimenter,  believing  them  to  be  deaf,  did  not  expect 
them  to  react,  and  hence  did  not  make  the  movements  which 
one  would  expect  in  the  opposite  situation.  The  most  honest 
introspection  will  not  enable  him  to  decide  whether  “uncon- 
scious and  involuntary”  movements  were  made.  If  would  have 
been  much  better  if  Kalischer  had  applied  some  form  of  control 
tests  with  the  experimenter  and  others  as  well  out  of  the  room. 

Kalischer,  however,  'was  satisfied  that  the  dogs  were  dis- 
criminating between  “exclusively  auditory  perceptions,.”  and  on 
that  assumption  proceeded  to  operate  on  the  auditory  center  as 


10 


HARRY  MILES  JOHNSON 


defined  by  Munk.  The  details  of  his  report  of  the  operative 
procedure  are  as  meager  as  are  those  of  his  behavior  tests. 

The  first  operation  was  the  extirpation  of  one  temporal  lobe 
from  an  animal  whose  cochlea  on  the  same  side  had  previously 
been  destroyed.  According  to  Munk  the  nervi  acustici  make 
a perfect  chiasmus,  and  this  operation  should  render  the  animal 
completely  deaf.  On  the  same  assumption,  if  the  cochlea  on 
one  side  were  completely  destroyed  and  the  auditory  area  on 
the  same  side  only  partially  extirpated,  deafness  to  some  tones 
only  — high  or  deep  according  as  the  anterior  or  posterior 
region  were  mutilated — should  be  produced.  Kalischer  re- 
ports, however,  that  his  animals  reacted  to  tones  as  before, 
no  matter  whether  extirpation  was  partial  or  complete.  There 
was  a noticeable  disturbance  in  responses  to  commands  and  more 
or  less  disturbance  of  orientation,  but  no  details  beyond  these 
statements  are  given  in  Kalischer ’s  report. 

Before  proceeding  to  extirpate  the  opposite  temporal  lobe 
from  these  animals,  Kalischer  allowed  from  four  to  five  weeks 
for  recovery,  during  which  he  continued  his  training.  He  ob- 
served no  change  in  the  animals’  discrimination.  “Nach  der 
ersten  Schlafenlappenextirpation  hatte  sich  kein  Unterscheid  in 
den  Verhalten  der  Tiere  bei  der  Dressurversuchen  gezeigt.  Die 
Tonunterschiedsempfindlichkeit  und  der  Reactionen  der  Tiere 
waren  die  gle'ichen  geblieben,  gleichgultig,  auf  welcher  Seite  die 
erste  operation  ausgefuhrt  worden  war.” 

The  extirpation  of  the  temporal  lobes,  Kalischer  says,  fol- 
lowed in  general  the  plan  of  Munk,  but  sometimes  a larger  area 
was  removed,  both  wider  and  deeper  (three-quarters  cm.  deep) 
and  sometimes  opening  the  ventricle. 

When  the  second  temporal  lobe  was  removed  from  some  ani- 
mals the  visual  area  also  was  injured,  Kalischer  asserts,  so  that 
“a  part  of  the  peripheral  visual  field  in  both  eyes  was  lost.”19 
After  this  operation  the  dogs  no  longer  reacted  to  spoken  com- 
mands, nor  did  they  show  by  pricking  of  the  ears  or  movements 
of  the  head  any  sensitivity  to  loud  noises.  Later  they  apparently 
began  to  resume  such  movements  at  loud  noises  and  very  loud 
commands,  but  did  not  learn  to  discriminate  among  them.  Be- 
fore the  operation  the  least  whistle  or  call  had  been  enough  to 

19  A reliable  method  of  making  an  accurate  test  of  the  dog’s  peripheral  vision 
would  be  valuable  and  interesting.  Kalischer  does  not  describe  his  method. 


HABIT  FORMATION  IN  THE  DOG 


11 


bring  them  forth.  Even  the  movements  of  the  head  and  ears 
at  noises  finally  disappeared  after  destruction  of  the  posterior 
corpora  quadrigemina  with  a needle.  The  animals’  reactions 
to  tones,  however,  were  much  less  affected.  Tests  were  resumed 
from  three  to  four  days  after  the  operation.  Kalischer  says 
that  some  disturbances  of  tonal  discrimination  followed — i.e., 
the  animals  did  not  always  react  and  inhibit  correctly.  (The 
percentage  of  error  and  the  number  of  trials  are  not  reported.) 
But  he  asserts  that  the  animals  “undoubtedly  discriminated” 
between  their  respective  food-tones  and  “Gegentone,”  and  as- 
cribes the  disturbance  wholly  to  the  shock  of  the  operation. 
This  may  be  correct,  but  evidence  is  lacking.  If  the  dogs  failed 
to  react  properly  to  the  different  tones  the  assumption  that 
their  failure  was  due  to  some  other  cause  than  inability  to  dis- 
criminate, is  a mere  guess. 

Kalischer  continues,  “from  the  second  week  on  the  animals 
began  to  exhibit  the  old  relations ; they  snapped  in  accustomed 
fashion  at  the  food-tone  and  shrank  back  at  the  ‘Gegentone;’ 
and  even  to  the  tones  adjacent  to  the  food-tone.”  Indeed,  the 
reactions  “appeared  almost  automatic,”  the  animals  “attended 
exclusively  to  the  food”  and  less  than  before  to  surrounding 
objects,  and  their  discrimination  seemed  improved  rather  than 
diminished.  They  reacted  correctly  when  chords  and  discords 
were  sounded  if  they  contained  the  food-tone.  It  was  possible 
to  retrain  even  the  “most  mutilated”  dogs  to  react  to  a new 
food-tone  and  to  inhibit  reaction  to  the  former  one.  Further, 
animals  not  trained  before  removal  of  both  temporal  lobes 
could  be  taught  to  make  the  same  discriminations,  although  they 
required  a longer  time  than  did  the  others,  since  they  were 
not  easily  accustomed  to  being  handled  and  to  making  de- 
finite movements. 

Kalischer  does  not  consider  the  possibility  that  the  dogs 
had  been  rendered  deaf  by  the  operation,  and  were  continuing 
their  choice  of  reaction  or  inhibition  of  reaction  to  certain  tones 
on  the  basis  of  rhythmic  or  habitual  order  of  presentation  of 
stimuli,  or  of  secondary,  extra-auditory  stimuli,  although  one 
would  naturally  suspect  that  this  were  the  case.  He  asserts 
that  no  other  conclusion  is  left  to  us  but  that  the  dogs  were 
deaf  to  noises  and  not  to  tone.  He  concludes  accordingly  that 
the  perception  of  noise  and  that  of  tone  are  different  functions; 


12 


HARRY  MILES  JOHNSON 


and  that  different  end-organs  and  different  centers  are  involved 
for  each.  The  center  for  noise  he  locates  in  the  temporal  lobe, 
the  afferent  pathway  to  which  passes  through  the  posterior 
corpora  quadrigemina.  The  end-organ  he  leaves  indeterminate. 
On  the  other  hand,  he  considers  that  the  cochlea  contains  the 
end-organs  for  tone ; and  that  the  center  for  tone  is  infra-cortical 
and  even  below  the  posterior  corpora  quadrigemina,  since  the 
only  known  auditory  pathways  to  the  cortex  pass  through  them. 
On  the  behavior  side  Kalischer  concludes  that  we  must  attribute 
to  the  dog  an  exceedingly  fine  sensitivity  to  absolute  pitch. 

That  the  defects  in  his  behavior  method  set  forth  above  render 
unwarranted  all  the  conclusions  which  he  draws  from  his  data, 
seems  to  me  clearly  evident. 

In  the  foregoing  pages  has  been  attempted  a rather  extensive 
criticism  of  Kalischer ’s  work.  This  to  some  readers  may  seem 
overdone.  But  to  me  it  seems  necessary  as  well  as  just,  because 
he  has  set  the  pattern  for  subsequent  work  by  other  investi- 
gators 20  whose  methods  have  been  of  the  same  general  type. 
His  work  has  commanded  praise  from  certain  physiologists,  as 
well  as  from  students  21  in  other  fields  to  whom  some  of  the 
difficulties  involved  in  a reliable  experimental  test  in  audition 
are  evidently  unfamiliar.  It  seems  proper  here  to  suggest  that 
Kalischer  would  hardly  have  adopted  so  crude  a method  and 
relied  so  uncritically  on  the  results  obtained  from  its  use,  had 
he  first  familiarized  himself  with  the  previous  investigations  in 
comparative  psychology  and  animal  behavior.  That  he  is  un- 
acquainted with  modern  behavior  methods  is  indicated  by  his 
claim  to  authorship  of  the  food-stimulus  method.  He  would 
hardly  have  advanced  such  a claim  had  he  been  familiar  with  the 
work  done  by  Lloyd  Morgan,  Thorndike,  Small,  Franz,  Yerkes 
and  Watson,  all  of  whom  and  many  others  had  been  using  the 
food-stimulus  method  for  years.  The  method  certainly  has 
great  antiquity.  After  this  point  had  been  raised  against  him 
22  he  repeated  the  claim  in  subsequent  writings. 

20  Swift,  W.  B.  Demonstration  eines  Hundes  dem  beide  Schlaefenlappen 
extirpiert  worden  sind.  Neurol.  Centbl.,  xxix,  pp.  686  ft. 

Also  Rothmann,  l.c.,  above. 

21  e.  g.  Bentley,  I.  M.  Psychological  Bulletin,  April  15,  1912. 

22  Franz,  S.  I.  Dressurmethode  f.  Zentralnervensystemuntersuchungen. 
Zentbl.  f.  Physiol.,  1907,  pp.  583  f.  See  also  Kalischer’s  reply  immediately  fol- 
lowing. . Also  Watson,  J.  B.  Psychological  Bulletin,  1908. 


HABIT  FORMATION  IN  THE  DOG 


13 


In  February,  1908,  Rothmann  23  reported  to  the  Physiolo- 
gische  Gesellschaft  of  Berlin  sOme  auditory  tests  which  he  had 
made  before  and  after  operations  on  several  dogs,  for  the  pur- 
pose of  testing  Kalischer’s  findings.  It  appears  that  about  the 
time  of  Kalischer’s  communication,  Rothmann  was  trying  to 
ascertain  the  function  of  the  posterior  corpora  quadrigemina. 
He  was  unwilling  to  accept  Kalischer’s  conclusion  that  the 
center  for  pitch  is  infracortical  and  lies  even  below  the  pos- 
terior corpora  quadrigemina.  His  reasons  are:  (1)  That  such 
an  assumption  does  too  much  violence  to  definite  localization 
theories  already  fairly  established;  (2)  that  the  dog’s  discrim- 
ination and  reactions  are  undoubtedly  very  complicated  proc- 
esses, and  accordingly,  to  make  them  independent  of  the  cere- 
brum would  be  practically  to  abandon  all  the  useful  doctrines 
of  the  relation  of  the  cortex  to  “psychical”  acts  which  prevail 
at  present  in  physiology  and  pathology.  Finally  he  suggests 
that  in  Kalischer’s  work  secondary  criteria  were  possibly  not 
excluded. 

He  adhered  to  the  following  routine  in  conducting  the  daily 
tests  on  each  animal:  The  stimulus  tones  were  struck  on  the 
same  organ  used  by  Kalischer  and  Munk.  The  experimenter 
sat  behind  it  “completely  concealed  by  the  high  pipes,  but  so 
that  he  could  observe  the  dog.”  “The  meat  was  laid  on  a foot- 
stool before  the  dog,  while  the  animal  scampered  freely  hither 
and  thither  about  the  room.  This  had  the  great  advantage 
that  the  tone  could  be  struck  while  the  dog  was  in  another  part 
of  the  room,  with  his  head  averted  from  the  food.”  A Diener 
was  posted  behind  the  stool,  to  drive  the  dog  away  when  he 
attempted  to  take  the  food  except  at  the  food-tone.  Rothmann 
had  suspected  that  Kalischer’s  dogs,  which  after  the  destruction 
of  both  corpora  quadrigemina  and  the  consequent  cessation  of 
all  signs  of  attention  to  other  noises  yet  continued  to  behave 
correctly  at  tones,  may  have  been  reacting  to  “unconscious 
helps,”  as  had  Der  kluge  Hans.  He  substituted  the  Diener  for 
the  experimenter  at  the  feeding-place,  apparently  considering 
that  the  untrained  Diener,  who,  however,  must  know  the  food- 
tones,  was  less  likely  to  give  the  animal  “unconscious  helps” 
than  would  be  the  experimenter,  who  was  “interested”  in  the 

23  Rothmann,  Max.  Ueber  die  Ergebnisse  der  Horprufung  an  dressierten 
Hunden.  Arch.  10  /.  Physiol.,  1908,  pp.  103  ff. 


14 


HARRY  MILES  JOHNSON 


problem.  As  a matter  of  fact,  perhaps  unconsciously,  Roth- 
mann  exposes  the  weakness  of  his  assumption.  He  says:  “If 
a wholly  disinterested  stranger,  were  introduced  for  the 
giving  of  the  food,  then  it  developed  that  the  dogs  undertook 
to  get  the  food  at  first  even  without  a tone , or  at  wrong  tones, 
but  only  in  the  beginning.  As  soon  as  they  had  accustomed 
themselves  to  the  change,  they  did  their  work  correctly.”  (Ital- 
ics mine.)  Here  it  is  evident  that  they  were  not  disturbed  by 
fear  of  the  stranger.  The  simplest  explanation  is  that,  missing 
the  first  Diener’s  threatening  signs,  they  reacted  at  random 
until  they  became  used  to  those  of  the  new  attendant. 

Rothmann  does  not  report  the  following  facts:  (i)  The  num- 
ber of  animals  used;  (2)  the  number  of  daily  trials;  (3)  the 
order  of  presentation  of  stimuli ; (4)  the  duration  of  the  respec- 
tive stimuli;  (5)  the  position  of  the  animal  with  reference  to 
the  food  when  the  respective  stimuli  were  given;  and  (6)  the 
experimenter’s  criterion  of  discrimination. 

The  importance  of  (1)  and  (2)  is  self-evident  to  the  experi- 
mental behaviorist ; that  of  (3)  and  (6)  has  already  been  pointed 
out  in  the  comment  on  Kalischer’s  work;  and  Rothmann ’s  ad- 
mission of  the  disturbing  effect  of  (4)  on  his  own  work  has  already 
been  quoted.  The  importance  of  (5) — -the  position  of  the  animal 
when  the  stimulus  is  given,  is  very  great,  as  it  may  easily  become 
a basis  of  reaction.  As  illustrative  of  this  point,  the  reader  is 
referred  to  page  53  of  this  work  for  a record  of  a control  test 
made  by  the  writer. 

Besides  training  to  tones,  Rothmann  trained  some  of  his 
animals  to  come  for  food  at  the  words  “ Komm  kerf  and  to 
refrain  from  coming  at  the  words  “ Kopf ■ scher ,”  both  combina- 
tions being  sung  on  the  same  tone.  Reaction  to  other  words  of 
command  was  also  taught. 

The  following  operative  and  post-operative  procedure  was 
followed:  Extirpation  of  both  posterior  corpora  quadrigemina 
was  performed  on  four  dogs.  Three  had  been  previously  trained. 
After  the  operation,  two  of  these  three  were  trained  for  about 
a month  to  discriminate  c-1024  d.v.  from  the  other  c’s  on  Roth- 
mann’s  organ,  but  without  success.  The  fourth  animal,  pre- 
viously trained  to  react  only  to  c-1024  d.v.,  and  which  had 
learned  the  problem  “faultlessly,”  was  again  subjected  to  the 
training  process  beginning  four  weeks  after  the  operation.  Three 


HABIT  FORMATION  IN  THE  DOG 


15 


weeks  were  spent  in  training  to  the  same  tone  without  success; 
following  which  twenty-three  days  were  spent  in  the  endeavor 
to  teach  the  animal  to  react  to  the  words  “ Mach  schon”  with 
the  same  outcome.  From  Rothmann’s  brief  account  one  gathers 
that  the  animal  reacted  when  noises  or  tones  were  made  but 
did  not  discriminate  among  them.  Post  mortem  showed  total 
destruction  of  the  posterior  corpora  quadrigemina  in  all  the 
animals. 

Extirpation  of  both  temporal  lobes  in  five  dogs  produced 
deafness  to  both  tone  and  noise  when  the  entire  area  described 
by  Munk  was  removed;  if  the  removal  was  not  complete,  some 
traces  of  the  reactions  remained.  A sixth  dog,  however,  not 
previously  trained,  having  been  deprived  of  both  temporal  lobes 
and  of  one  convolution  of  the  gyrus  sylviacus,  was  “success- 
fully trained’ * in  three  weeks  to  react  only  to  c-256  d.v.  Seven 
days  sufficed  to  perfect  reaction  to  the  words  “ Nimm  Fleisch .” 

In  two  dogs  not  previously  trained,  both  internal  geniculate 
bodies  were  destroyed.  Neither  could  be  trained  to  respond  to 

either  tone  or  noise.  From  these  results  Rothmann  concludes 

♦ 

that  the  dog’s  auditory  center  lies  in  the  temporal  region,  but 
that  it  extends  over  a wider  area  than  that  defined  by  Munk. 
According  to  him  the  pathway  from  the  end-organ  passes  through 
the  posterior  corpora  quadrigemina  and  the  internal  geniculate 
bodies. 

The  anatomical  findings  thus  announced  are  certainly  less 
revolutionary  and  less  spectacular  than  are  those  of  Kalischer, 
and  conform  fairly  to  the  generally  accepted  view.  It  should 
be  remembered,  nevertheless,  that  Rothmann’s  experimental  pro- 
cedure is  as  unreliable  as  Kalischer ’s,  if  indeed  not  more  so. 

Kalischer  published  in  1909  a report 24  of  continued  work 
done  on  reactions  of  dogs  to  musical  tones.  His  conclusions 
from  his  former  work  had  left  the  end-organ  for  tone  indeter- 
minate, and  he  wished  to  test  the  theory  of  Helmholtz  regarding 
the  function  of  the  cochlea  and  the  vestibular  apparatus.  In 
this  same  report  he  gives  account  of  its  extension  to  olfactory 
and  color-vision  tests  on  the  dog.  Apropos  of  the  last  men- 
tioned part  of  his  work  it  might  be  remarked  that  Kalischer ’s 

24  Kalischer,  Otto.  Weitere  Mitteilung  ueber  die  Ergebnisse  der  Dressur  als 
physiologischer  Untersuchungsmethode  auf  den  Gebieten  des  Gehor — ,Geruchs- 
und  Farbensinns.  Arch.  f.  Physiol.,  1909. 


16 


HARRY  MILES  JOHNSON 


apparatus  is  subject  to  several  gross  defects  which  had  been 
eliminated  in  color- vision  tests  on  animals  made  by  Yerkes  some 
years  before  Kalischer ’s  work  was  published,  by  the  use  of  the 
food-stimulus  method. 

The  auditory  tests  reported  in  this  article  were  carried  on 
by  the  same  method  as  was  employed  in  the  earlier  work,  except 
that  some  animals  were  trained  to  respond  to  as  many  as  three 
(single)  food-tones — -high,  middle  and  deep.  Different  animals 
responded  to  tones  from  F2  to  f3,  sounded  on  the  harmonium. 
Kalischer  says  that  in  the  beginning  of  this  experiment  when 
the  food-tone  was  sounded  he  helped  the  animals  perform  their 
reactions;  but  that  later  they  performed  them  voluntarily 
“without  any  help  being  given.”  Most  of  the  animals  had 
already  been  trained  to  react  to  one  food-tone,  and  Kalischer 
tells  us  that  the  training  had  to  be  continued  long  enough  for 
the  new  food-tone  to  become  “fixed  in  memory”  before  reac- 
tion became  sure.  How  long  a time  was  required  he  does  not  say. 

After  the  animals  had  been  trained  to  two  food-tones,  one 
high  and  the  other  deep,  one  labyrinth  was  completely  de- 
stroyed, making  the  animal  wholly  deaf  on  that  side.  The 
method  used  was  the  mastoid  opening  of  Heidenhain.  Destruc- 
tion of  both  cochlea  and  vestibular  apparatus  was  made  com- 
plete. Training  was  continued  for  two  or  three  weeks  after 
the  operation,  which  had  not  damaged  the  dogs’  accuracy  in 
discrimination.  By  the  same  method  the  second  cochlea  was 
then  exposed,  and  the  part  of  the  cochlea  desired  was  removed 
by  first  piercing  the  “knee-capsule”  covering  the  cochlea  with 
a fine  drill-point,  and  removing  the  parts  with  a needle.  One 
animal  in  particular,  trained  before  the  operation  to  respond 
only  to  food-tones  Ai  and  c3,  suffered  no  loss  of  accuracy  in  dis- 
criminating between  these  tones  and  all  others.  Post  mortem 
showed  entire  destruction  of  one  cochlea,  and  removal  of  the 
other  as  far  down  as  the  lowest  turn.  Only  this  small  portion 
of  the  cochlea  and  the  vestibular  apparatus  were  left  intact. 
The  part  of  the  organ  of  Corti  and  of  the  membrane  of  Reissner 
contained  in  this  part  of  the  cochlea,  and  also  the  cells  of  the 
spiral  ganglion  which  belong  to  this  turn  of  the  cochlea,  were 
uninjured.  Reaction  to  the  spoken  words  “Seeks”  and  “ Drei” 
was  also  perfect,  the  animal  being  allowed  to  take  food  when 
they  were  spoken. 


HABIT  FORMATION  IN  THE  DOG 


17 


In  another  animal  post  mortem  showed  that  only  the  lowest 
turn  of  the  cochlea,  with  the  part  of  the  organ  of  Corti  and  of 
the  ganglion  cells  contained  in  it,  was  destroyed.  The  parts 
lying  in  the  middle  turn  of  the  cochlea,  however,  were  atro- 
phied, and  the  vestibular  apparatus  was  slightly  damaged.  This 
animal,  which  had  been  trained  to  react  only  to  Bi  and  c3  as 
food-tones,  and  to  spoken  words,  and  from  which  previous  to 
this  operation  the  other  cochlea  had  been  removed,  had  reacted 
both  to  tone  and  to  noise  as  had  normal  animals. 

From  other  animals,  one  cochlea  having  been  removed,  one 
side  of  the  remaining  cochlea  was  also  extirpated,  leaving  , the 
other  side  intact,  and  not  injuring  the  vestibular  apparatus. 
These  after  the  operation  did  not  react  to  their  food-tones  until 
helped.  They  had  lost  their  “absolute”  sensitivity  to  pitch, 
says  Kalischer,  but  could  still  be  made  to  discriminate  between 
food-tones  and  “Gegentone,”  even  if  the  difference  was  only 
half  a tone.  In  other  animals  in  which  the  vestibular  apparatus 
was  more  or  less  injured  by  this  operation,  disturbances  corres- 
ponding to  the  degree  of  injury  were  observed.  That  is  to  say, 
they  could  not  be  made  to  differentiate  between  tones  lying 
close  together  in  pitch,  but  could  differentiate  between  tones 
lying  farther  apart. 

From  these  data  Kalischer  concludes  that  the  theory  of  Helm- 
holtz and  others  that  the  different  parts  of  the  cochlea  and  of 
the  basilar  membrane  act  selectively  as  receptors  of  long  or 
short  sound-waves,  is  untenable.  Also,  that  the  vestibular  appa- 
ratus possesses  an  auditory  function,  and  is  necessary  for  pitch- 
discrimination.  Further,  that  all  clang -analysis  takes  place  “in 
the  peripheral  end-organs  of  the  nervus  acusticus.” 

In  an  Ankang  to  this  part  of  his  report  Kalischer  says  that 
some  of  his  dogs  were  brought  to  discriminate  between  tri- 
chords as  well  as  between  simple  tones ; for  instance,  an  animal 
trained  to  react  to  e1  and  to  inhibit  reaction  to  e\?\  would  also 
react  to  the  chord  c^g1  and  inhibit  reaction  to  the  chords 
c1  eb1  g1,  c#1  e#1  g#\  d1  f#  a1,  etc.  He  further  says  that  by  the  use 
of  a mouth  harmonica  he  was  able  to  demonstrate  in  experiments 
conducted  in  the  stable,  that  the  ass  also  possesses  sensitivity 
to  “absolute  pitch.”  The  total  time  required  for  this  demon- 
stration was  about  one  and  one -half  weeks. 


18 


HARRY  MILES  JOHNSON 


Swift  25  who  was  interested  in  the  “psychical”  processes 
involved  in  the  reactions  of  Kalischer’s  and  Rothmann’s  dogs, 
as  well  as  in  their  localization  theories,  trained  two  female  dogs 
“after  the  method  of  Kalischer,”  to  discriminate  between  c1 
and  e2,  sounded  on  trumpets.  The  c1  was  the  food-tone.  Four- 
teen days  sufficed  to  perfect  the  reactions.  The  number  of 
trials  a day  is  not  given.  No  control  tests  showing  that  the 
animals  were  not  reacting  to  other  than  auditory  stimuli  are 
reported.  A month  of  rest  was  allowed  before  operating. 

On  the  first  dog,  extirpation  of  the  left  temporal  .lobe  was 
performed.  This,  according  to  Swift,  produced  right  hemian- 
opia.  He  does  not  say  how  this  fact  was  determined.  The 
reactions  to  tone  were  undisturbed  when  the  tests  were  resumed, 
three  days  after  the  operation.  Ten  days  later  the  right  tem- 
poral lobe  was  also  extirpated.  This,  Swift  says,  rendered  the 
animal’s  blindness  nearly  total,  and  also  produced  left  hemi- 
plegia. Discrimination  between  the  tones  was  not  disturbed. 
The  same  operations  were  performed  on  the  second  dog,  but 
both  lobes  were  removed  at  once.  She,  too,  discriminated  as 
unfailingly  as  before.  This,  S\yift  thinks,  demonstrates  that  the 
center  for  pitch  cannot  lie  in  the  temporal  lobe.  He  does  not 
agree  with  Kalischer,  however,  that  the  center  for  tone  can  be 
infra-cortical.  He  argues  that  the  dogs’  reactions  involve  a 
complex  “intellectual  process,”  and  reveal  a well  developed 
“ability  to  think:”  hence,  that  the  cortex  must  be  involved.* 
He  believes,  therefore,  that  the  center  lies  in  the  cortex,  but 
outside  the  temporal  region. 

If  Swift  followed  the  method  of  Kalischer,  as  he  asserts,  then 
the  animals  could  have  reacted  to  many  other  cues  than  audi- 
tory, as  has  been  shown  in  the  remarks  on  Kalischer’s  first 
experiment.  Nor  is  it  safe  to  assume  on  the  results  of  casual 
tests  that  a dog  is  or  is  not  suffering  from  defective  vision. 
Extensive  observation  of  the  reactions  of  blind  dogs  to  con- 
trolled stimuli,  some  data  of  which  are  included  in  a later  part 
of  this  work;  and  tests  by  standard  methods  on  the  vision  of 
normal  dogs,  made  by  Haggerty  and  by  myself,  have  yielded 
results  quite  at  variance  with  the  popular  attribution  of  visual 
keenness  to  the  dog.  Further  it  should  be  said  that  Swift’s 

25  Swift,  W.  B.  Demonstration  eines  Hundes  den  beide  Schlaefenlappen 
extirpiert  worden  sind.  Neurol  Centbl.,  xxix,  pp.  686  ff. 


HABIT  FORMATION  IN  THE  DOG 


19 


animals  may  have  been  reacting  to  pain  and  not  to  tone ; an 
e-640  d.v.  trumpet-tone,  sounded  at  close  quarters  in  a small 
room,  is  certainly  both  loud  and  high  enough  to  occasion  pain 
in  the  human  subject.  And  finally,  it  is  a commonplace  that 
Swift’s  ascription  to  the  dog  of  “intellectual”  processes  and  a 
highly  developed  “ability  to  think,”  is  unscientific.  There  is 
no  possible  means  by  which  we  may  experience  an  approxima- 
tion to  the  dog’s  “content,”  in  the  first  place;  and  besides,  we 
can  interpret  his  behavior  adequately  and  far  more  surely  with- 
out relying  upon  a construct.  Indeed,  we  can  explain  his  reac- 
tions quite  satisfactorily  on  the  assumption  that  he  has  no 
mental  content;  and  the  assumption  can  no  more  be  disproved 
than  can  the  one  of  Swift’s. 

As  appears  in  the  foregoing  discussion  of  work  done  by  other 
investigators,  the  problem  of  localization  of  the  auditory  center 
has  been  left  by  them  in  an  unsatisfactory  state.  Rothmann 
and  Munk  place  the  auditory  center  in  the  temporal  region; 
Munk  asserts  that  different  portions  of  the  region  perform  highly 
differentiated  functions.  Kalischer  insists  that  the  center  f r 
pitch  is  infracortical ; that  tone -discrimination  is  made  in  the 
“peripheral  end-organs  of  the  nervus  acusticus and  that  the 
center  for  noise  is  another  center  than  that  for  pitch.  Swift 
tells  us  .that  the  center  must  be  cortical,  but  that  he  has  demon- 
strated that  it  cannot  lie  in  the  region  pointed  out  by  Munk 
and  Rothman.  As  has  been  pointed  out,  the  methods  of  con- 
ducting behavior  tests  employed  by  all  these  experimenters  are 
decidedly  crude  and  their  widely  divergent  conclusions  may  be 
explained  at  least  partially  by  reference  to  the  methods  of 
controlling  the  animals’  behavior. 

PRELIMINARY  EXPERIMENTATION 

In  April,  1910,  at  the  suggestion  of  Professor  Watson,  I 
began  as  an  experiment  in  comparative  psychology  a series  of 
tests  on  the  audition  of  dogs,  in  the  hope  of  accomplishing  the 
following  purposes: 

1.  To  see  whether  the  behavior  results  of  Kalischer  and 
others  could  be  confirmed  by  tests  made  under  more  reliable 
conditions  of  control. 

2.  To  devise  a satisfactory  method  of  testing  the  limits  of 
pitch-discrimination  in  the  higher  vertebrates. 


20 


HARRY  MILES  JOHNSON 


3.  To  find  the  difference-threshold  for  pitch  in  the  dog. 

4.  If  preliminary  results  should  justify  the  attempt,  to  repeat 
the  tests  on  animals  on  which  after  training,  extirpation  opera- 
tions had  been  performed  by  a competent  surgeon,  and  attempt 
to  interpret,  the  disturbances  which  might  result  in  the  light 
of  the  post  mortem  examinations. 

The  statement  may  properly  be  made  now  that  neither  of 
the  two  goals  last  mentioned  has  as  yet  been  reached. 

The  animals  used  were  two  females,  litter  sisters,  mongrels, 
littered  June  15,  1906.  At  about  their  second  day  of  life  a 
surgeon  in  the  state  hospital  for  the  insane  at  Wards  Island, 
New  York,  had  assured  the  continuance  of  temporary  blindness 
as  long  as  might  prove  desirable,  by  first  scarifying  the  edges 
of  the  lids  and  then  uniting  them  with  stitches.  This  caused 
the  upper  and  lower  lids  to  grow  fast  together  before  the  ninth 
day,  at  which  time  the  puppy’s  eyes  ordinarily  open.  During 
the  preliminary  experiment  described  herein  the  dogs  were  still 
in  the  blind  state.  When  this  work  was  begun  they  had  been 
in  the  laboratory  for  over  a year  but  no  experiments  of  con- 
sequence had  been  made  with  them.  Both  were  laboratory 
pets  and  very  affectionate,  but  rather  nervous  in  strange  situa- 
tions. 

It  seemed  best,  in  order  to  obtain  decisive  results,  to, present 
the  animal  with  at  least  fifteen  stimuli  at  each  daily  test.  If 
a small  number — say  five,  is  chosen,  variation  in  the  order  of 
presentation  is  too  greatly  limited ; and  if  the  animal  is  nervous 
at  first  the  record  is  not  a.  fair  indication  of  his  discriminatory 
work. 

The  animals  used  in  this  experiment  were  fed  once  a day — 
at  the  time  set  for  the  experiment,  which  was  early  in  the  after- 
noon. No  food  was  given  until  the  day’s  work  was  begun.  If 
the  animal  appeared  unduly  eager  to  begin  work  one  or  two  bits 
of  meat  were  usually  given  before  the  stimulus  was  presented, 
in  order  to  make  the  dog  better  contented.  After  each  day’s 
series  each  animal  was  allowed  to  eat  as  much  as  she  desired  at 
the  time.  The  food  was  scrap  meat,  thoroughly  cooked  by  boil- 
ing, and  mixed  with  stale  bread  soaked  in  its  liquor.  Milk  was 
also  given  from  two  to  seven  times  a week.  Both  these  and  the 
other  animals  used  in  later  work  remained  in  splendid  condition 
throughout  the  experimental  work. 


HABIT  FORMATION  IN  THE  DOG 


21 


It  seemed  better  also  to  adopt  a different  test  of  discrimina- 
tion from  that  used  by  Kalischer,  Rothmann  and  Swift.  This, 
as  has  been  mentioned,  was  to  allow  the  animal  to  take  food  at 
one  or  more  tones  and  to  refrain  from  it  at  others.  If  an  animal 
is  hungry  and  eager  to  obtain  food,  one  would  expect  a ten- 
dency to  react  to  the  mere  striking  of  any  tone;  while  if  the 
animal  is  timid  there  may  be  a tendency  to  inhibit  reaction,  even 
though  the  tone  were  “recognized”  as  the  food-tone.  So,  to  the 
two  tones  used  as  stimuli,  two  reactions  quite  different  were 
chosen;  to  the  deeper  tone  the  animal  was  trained  to  react  by 
placing  her  forefeet  on  a chair  at  the  operator’s  left,  and  waiting 
there  for  food;  to  the  higher  tone,  by  mounting  a low  box  at 
the  operator’s  right,  and  “ sitting  down  ” on  it  until  fed.  Between 
stimuli  the  animal  sat  on  the  floor,  at  the  experimenter’s  feet. 
Food  was  given  after  a correct  reaction  had  been  chosen.  In 
case  of  incorrect  choice  she  was  recalled  without  being  fed  unless 
she  was  unusually  nervous,  in  which  event  occasionally  she  was 
allowed  to  perform  the  correct  reaction  and  take  food,  the  reac- 
tion being  recorded  as  an  error.  The  problem  was  considered 
“learned”  when  the  animal  had  performed  three  successive 
daily  series  of  reactions  without  error. 

The  two  stimulus-tones  chosen  were  middle  c (256  d.v.)  and 
the  g above  (384  d.v.).  The  tones  were  sounded  at  first  on  two 
standard  tuning  forks,  mounted  on  wooden  resonators,  and 
struck  by  hand.  The  forks  were  placed  close  together  on  a 
shelf  in  front  of  the  experimenter,  and  rested  on  heavy  cotton 
felt  pads.  Their  relative  position  was  frequently  changed. 
Later  in  this  experiment  the  tones  were  sounded  also  on  several 
Stern  variators,  large  and  small,  blown  from  a Stern  tank,  and 
carefully  tuned  each  day  to  the  tuning  forks.  The  merits  and 
defects  of  this  apparatus  will  be  discussed  later  in  this  paper. 
Each  tone  was  sounded  until  the  animal  had  reacted — usually 
not  more  than  one  and  one-half  to  two  seconds. 

For  about  six  days,  the  animals,  both  of  which  were  seem- 
ingly frightened  when  the  forks  were  first  struck  in  their  pres- 
ence, were  “put  through”  the  proper  reactions — to  one  tone 
several  times  and  then  to  the  other  for  the  rest  of  the  series.  As 
soon  as  they  showed  a tendency  to  react  voluntarily  they  were 
allowed  to  work  without  consciously  given  help,  at  least,  from 
the  experimenter.  Records  were  taken  from  this  point  on. 


22 


HARRY  MILES  JOHNSON 


Four  problems  were  given: 

1.  Discrimination  between  the  two  tones  sounded  on  tuning 
forks  struck  by  hand. 

2.  Discrimination  between  the  two  tones  sounded  on  the 
blown  variators. 

3.  Discrimination  between  the  two  tones  spunded  on  forks 
and  on  large  and  small  variators  indifferently. 

4.  Discrimination  between  chords  containing  one  and  the 
other  stimulus-tones,  respectively. 

The  results  are  summarized  in  the  following  table : 


Problem 

Dog 

Began 

Finished 

Days 

worked 

Trials  required 
for  learning 

1 

1 

4/19 

5/  7 

19 

285 

2 

4/18 

5/14 

27 

405 

2 

1 

5/12 

5/19 

8 

120 

2 

5/19 

5/24 

6 

90 

. 3 

1 

6/  1 

6/11 

12 

150 

2 

6/  1 

7/18 

40 

600 

4 

1 

8/  6 

10/  1 

41 

615 

2 

8/  4 

9/30 

44 

660 

The  tables  showing  the  daily  percentage  of  error  are  found 
on  pp.  24ft.  The  longer  learning -time  of  Dog  2 in  experiment 
3 was  due  to  disturbance  by  the  falling  of  a piece  of  apparatus 
duing  an  experiment.  She  refused  to  work  for  nine  days  and 
then  resumed  responses  of  any  kind  only  after  a great  deal  of 
coaxing  and  petting. 

Care  was  taken  to  sound  the  tones  with  varying  degrees  of 
intensity.  The  tones  of  the  variators  can  be  made  faint  or  loud 
at  will  by  increasing  or  lessening  the  diameter  of  the  opening 
of  the  air- valve  leading  to  each  pipe.  Such  a change  produces 
also  a change  of  pitch.  The  latter  must  be  corrected  by  re- 
tuning  to  the  fork.  Further  the  same  stimulus -tones  can  be 
blown  on  any  one  of  two  or  three  variators.  By  this  means 
tones  of  the  same  fundamental  pitch,  but  of  quite  different 
timbre,  were  given.  It  was  thought  that  this  might  prevent 
the  animal  from  reacting  to  constant  differences  of  intensity 
and  timbre.  The  relative  position  of  the ' different  resonators 
was  also  frequently  interchanged,  to  prevent  possible  localiza- 
tion from  becoming  a factor. 


HABIT  FORMATION  IN  THE  DOG 


23 


In  experiment  4 the  following  chords  were  used: 


(1)  Con- 
taining c'  (256  d.v.)  c'-e;  c'-e'c";  g-c'-e';  c'-eb';  c'-eb'-c"; 
g -c'-eb';  a-c';  f-c';  f-c'-a' ; a-c'f';  c'-a'-f';  (2)  containing  g' 

(384  d.v.);  g'-b;  g'-b'-g";  g'-bb';  g'-bb'-g';  e'-g'-c";  eb'-g'-c"; 
g'-b'-d';  d'-g';  d-g'-b';  g'-b'-d".  These  chords  were  used  in- 
differently, regard  being  paid  only  to  which  of  the  two  stimulus- 
tones  was  contained  in  the  chord.  That  the  chord  might  be 
sounded  at  once,  an  extra  valve  was  put  on  the  main  pipe  lead- 
ing from  the  tank,  which  was  to  be  kept  closed  except  when  the 
stimulus  was  given.  Thus  the  stops  opening  the  valve  leading  to 
each  variator  could  be  pulled  out  as  desired,  and  when  the  main 
valve  was  opened  the  entire  chord  would  be  sounded  at  once. 

The  results  of  this  experiment  approximate  closely  those 
obtained  by  Kalischer  and  Rothmann.  I have  never  observed, 
however,  what  they  both  report,  namely,  that  after  a few  trials 
have  been  given  the  animal  becomes  “fatigued.”  If  the  animal 
is  left  alone  as  many  as  thirty  trials  may  be  given  in  control 
tests,  evoking  a prompt  response  each  time.  This  makes  me 
suspect  that  the  failure  of  Kalischer ’s  dogs  to  react  to  the  food- 
tones,  if  the  latter  in  a four  or  five  minute  series  were  “allowed 
to  sound  often  one  after  the  other,  ’ ’ was  due  to  a lack  of  discrim- 
ination rather  than  to  mere  fatigue. 

A control  test  of  retention  was  given  sixty  days  after  the 
last  problem  had  been  “learned.”  Following  a private  discus- 
sion of  Kalischer’s  contention  that  the  dog  has  an  “exceedingly 
fine  sensitivity  to  absolute  pitch,”  (of  which,  however,  I have 
never  been  convinced)  I invited  the  members  of  the  psychological 
journal  club  to  witness  a test  of  the  animals’  ability  to  react 
properly  to  their  old  stimulus-tones.  The  animals  had  not 
worked  on  the  problem  since  it  had  been  discontinued — in  fact, 
they  were  then  engaged  in  learning  to  open  a problem-box  for 
their  daily  food.  The  two  stimulus-forks  used  in  the  first  prob- 
lem were  used  and  struck  as  before.  Each  dog  was  given  eight 
stimuli,  in  the  order  indicated  by  one  of  the  observers  watching 
the  experiment  through  a glass  door.  Each  dog  reacted  with- 
out error.  Dog  1 was  sniffing  at  the  place  on  the  floor  where 
her  problem-box  usually  stood,  and  when  the  first  fork  was 
struck,  merely  crouched  and  kept  sniffing  hastily  at  the  floor 
where  she  stood.  When  after  perhaps  two  seconds  the  fork  was 
struck  again,  she  again  crouched  and  in  some  confusion  found 


24 


HARRY  MILES  JOHNSON 


her  way  to  the  chair  and  mounted  it  properly, 
reactions  and  all  those  of  Dog  2 were  prompt. 


All  her  other 


TABLE  1 

Discrimination  Between  Forks  ct256  d.v.  and  g-384  d.v.  Struck  by  Hand 


Dog  1 

Dog  2 

Day 

% Accuracy 

% Accuracy 

1 

47 

40 

2 

53 

33 

3 

60 

47 

4 

40 

73 

5 

40 

40 

6 

47 

47 

7 

53 

53 

8 

60 

53 

9 

80 

47 

10 

66 

47 

11 

86 

67 

12 

73 

47 

13 

86 

80 

14 

80 

67 

15 

93 

87 

16 

93 

80 

17 

100 

87 

18 

100 

87 

19 

100 

93 

20 

93 

21 

80 

22 

87 

23 

100 

24 

87 

25 

100 

26 

100 

27 

100 

TABLE  2 

on  Between  Variators  c-256  d.v. 

Dog  1 

Dog  2 

Day 

% Accuracy 

% Accuracy 

1 

80 

80 

2 

73 

80 

3 

80 

93 

4 

86 

100 

5 

86 

100 

6 

100 

100 

7 

100 

8 

100 

HABIT  FORMATION  IN  THE  DOG 


25 


TABLE  3 

Discrimination  Between  c-256  d.v.  and  g-384~d.v.  Struck  on  Forks 
and  Variators  Indiscriminately 


Dog  1 

Dog  2 

Day 

% Accuracy 

% Accuracy 

1 

47 

60 

2 

40 

66 

3 

53 

20 

4 

47 

00 

5 

73 

00 

6 

73 

00 

7 

87 

00 

8 

100 

00 

9 

100 

10 

10 

100 

00 

11 

20 

12 

33 

13 

47 

14 

40 

15 

66 

16 

80 

17 

80 

18 

47 

19 

40 

20 

60 

21 

53 

22 

53 

23 

73 

24 

66 

25 

73 

26 

80 

27 

80 

28 

66 

29 

73 

30 

87 

31 

87 

32 

80 

33 

93 

34 

80 

•35 

93 

36 

93 

37 

93 

38 

100 

39 

100 

40 

100 

26 


HARRY  MILES  JOHNSON 


TABLE  4 

Discrimination  Between  Chords  Containing  c-256  d.v.  and  g-384  d.v. 
Sounded  on  Variators 


Dog  1 

Dog  2 

Day 

% Accuracy 

% Accuracy 

1 

67 

73 

2 

47 

60 

3 

67 

47 

4 

67 

60 

5 

73 

80 

6 

73 

60 

7 

60 

87 

8 

73 

87 

9 

47 

80 

10 

73 

87 

11 

80 

87 

12 

73 

80 

13 

87 

80 

14 

80 

87 

15 

80 

53 

16 

87 

80 

17 

53 

67 

18 

47 

73 

19 

73 

80 

20 

80 

73 

21 

87 

87 

22 

87 

73 

23 

100 

60 

24 

67 

73 

25 

80 

73 

26 

87 

80 

27 

87 

87 

28 

80 

87 

29 

80 

87 

30 

87 

80 

31 

73 

53 

32 

87 

60 

33 

87 

80 

34 

80 

80 

35 

93 

80 

36 

93 

80 

37 

93 

93 

38 

100 

47 

39 

100 

73 

•40 

100 

93 

41 

87 

42 

100 

43 

100 

44 

100 

HABIT  FORMATION  IN  THE  DOG 


27 


Although  these  results  taken  at  their  face  value  seem  to  con- 
firm those  of  Kalischer  and  Rothmann,  yet  they  were  not  wholly 
satisfactory.  The  experimenter  had  been  in  the  room,  near  the 
dogs,  throughout  the  experiment.  While  he  was  not  yet  trained 
to  observe  and  to  guard  against  the  giving  of  less  noticeable 
secondary  cues,  yet  on  casting  the  results  it  was  easy  to  recall 
many  times  when  an  animal  had  changed  her  reaction  if  the 
operator  happened  to  turn  his  head,  shift  his  body -weight  from 
one  foot  to  the  other,  or  catch  his  breath.  Also,  that  if  the 
stimulus-tone  was  not  damped  as  soon  as  the  animal  had  se- 
lected her  feeding-place,  she  would  sometimes  go  hastily  to 
the  other.  Further  there  was  room  for  doubt  whether  the  order 
of  presentation  had  been  sufficiently  irregular,  as  in  the  records 
of  the  animal’s  work  on  the  first  two  problems,  there  were  shown 
only  the  number  of  right  and  wrong  reactions  respectively  to 
each  stimulus-tone,  the  order  of  presentation  not  being  given. 
These  facts  being  considered  it  seemed  better  not  To  rely  on  the 
results  at  hand  until  other  tests  could  be  made  in  which  these 
possible  disturbing  factors  were  eliminated. 

Accordingly  in  the  summer  of  1911  the  same  two  animals 
were  subjected  to  control  tests,  which,  through  the  kindness  of 
Professors  Angell  and  Carr,  were  performed  in  the  laboratory 
of  the  University  of  Chicago.  The  two  stimulus-tones  chosen 
were  middle  c-256  d.'v.  and  e'~320  d.v.  It  was  believed  that 
the  animals  would  quickly  learn  to  discriminate  between  these 
and  that  other  tones  could  then  be  introduced,  to  which  yet 
different  reactions  could  be  made. 

In  these  tests  the  stimulus-tones  were  struck  on  standard 
forks  by  an  assistant26  who  sat  in  a room  twelve  feet  away, 
separated  from  the  animal -room  by  two  partitions,  one  of  which 
was  a nine -inch  brick  wall.  A wooden  tube  four  by  six  inches 
in  cross-section  was  used  to  convey  the  sound  into  the  animal- 
room.  Between  stimuli  the  animal  was  confined  in  a cage  just 
under  the  sound-pipe,  and  when  the  stimulus-tone  was  struck, 
was  released  by  the  experimenter’s  pulling  a string  from  where 
he  stood,  in  the  room  adjoining,  by  which  act  the  door  of  the 
cage  was  noiselessly  released.  In  the  opposite  corner  of  the 

26  This  part  of  the  experiment  was  conducted  with  the  assistance  of  Mr.  J. 
W.  Shields,  then  a graduate  student  in  the  University  of  Chicago,  to  whom  my 
thanks  are  due. 


28 


HARRY  MILES  JOHNSON 


room  were  two  food-boxes,  each  above  a chair  which  the  animal 
was  to  mount  with  her  fore -feet.  The  two  chairs  were  fastened 
with  sides  together,  and  with  their  fronts  secured  to  the  wall, 
so  that  the  animal  had  to  face  west  in  mounting  the  chair  to 
be  associated  with  the  tone  of  the  c-fork ; and  east  in  mounting 
the  one  to  be  associated  with  the  tone  of  the  e-fork.  When  proper 
choice  was  made  food  was  dropped  on  to  the  chair  from  a chute 
above,  which  was  opened  by  the  pulling  of  a string  in  the  hand 
of  the  experimenter.  In  case  of  incorrect  choice  the  animal  was 
recalled  without  being  fed.  The  reactions  were  observed  by  the 
experimenter  from  without  the  room,  who  watched  the  work 
through  a hole  in  the  wall  three  inches  square. 

In  the  beginning  of  this  experiment  the  animals  were  first 
given  each  tone  separately,  and  “put  through”  by  the  operator. 
After  eight  or  ten  stimuli  had  been  given  the  animal  showed  a 
tendency  to  go  to  the  box  of  her  own  accord.  After  each  animal 
had  performed  fifty  consecutive  reactions  to  the  c-fork  correctly 
without  being  put  through,  she  was  trained  to  go  to  the  other 
box  at  the  striking  of  the  e-fork  and  allowed  a like  number  of 
reactions.  Then  both  stimuli  were  given  irregularly  in  a given 
series,  and  the  animals’  unaided  reactions  were  recorded.  Each 
early  developed  a “position  habit,”  at  first  usually  choosing 
the  box  where  ; he  was  last  fed  or  avoiding  the  one  from  which 
she  has  last  been  recalled  without  being-  fed.  Then  followed 
in  each  dog  a preference  for  one  box  or  the  other,  causing  its 
selection  from  70%  to  90%  of  the  chances.  Then  each  dog 
acquired  a rhythmical  habit,  going  to  one  box,  now  to  the  other, 
regardless  of  the  stimulus  presented.  To  break  this  up  the 
animal  was  worked  against  her  preference — the  order  of  pre- 
sentation being  so  arranged  that  the  animal’s  method  would 
seldom  secure  food  for  her.  Later  both  animals  reacted  irreg- 
ularly, but  as  appears  in  table  5,  with  little  regard  to  the 
stimulus  given. 

After  37  days — 505  trials  each,  the  experiment  had  to  be 
interrupted.  There  was  little  evidence  of  discrimination  in  the 
dogs  at  the  end  of  the  test. 

There  were  some  indications,  however,  that  they  might  be 
failing  to  react  correctly,  not  because  of  inability  to  discrimi- 
nate, but  because  of  lack  of  “attention.”  If  on  leaving  the  cage 
the  animal  immediately  began  a wide  detour  to  the  right  or 


HABIT  FORMATION  IN  THE  DOG 


29 


left  in  going  to  the  food-box,  the  reaction  was  nearly  always 
correct ; but  if  she  started  by  a middle  path  toward  the  boxes, 
which  were  near  together,  the  reaction  was  incorrect  as  often, 
at  least,  as  correct.  It  was  usually  possible  for  the  experimenter 
to  predict  from  the  animal’s  breathing  when  she  was  about  to 
become  indifferent.  This  stage  was  observed  sometimes  in  the 
beginning  of  a series,  sometimes  only  about  the  middle,  and 
sometimes  near  the  end.  It  could  hardly  be  interpreted  there- 
fore, as  fatigue,  especially  since  the  animal  would  always 
make  some  choice  very  quickly.  The  “delayed  reaction”  factor 

TABLE  5 

Discrimination  Between  Struck  Forks  c-256  d.v.  and  e-320  d.v. 

(Control  experiment,  Chicago) 


Dog  1 

Dog  2 

Day 

% Accuracy 

% Accuracy 

1 

00 

10 

2 

00 

00 

3 

00 

00 

4 

33 

40 

5 

40 

47 

6 

40 

73 

7 

27 

40 

8 

53 

10 

9 

60 

40 

10 

67 

53 

11 

73 

40 

12 

27 

53 

13 

33 

33 

14 

53 

53 

15 

33 

73 

16 

30 

27 

17 

30 

33 

18 

60 

47 

19 

80 

33 

20 

50 

60 

21 

70 

40 

22 

70 

60 

23 

70 

53 

24 

50 

53 

25 

20 

40 

26 

40 

40 

27 

40 

53 

28 

60 

10 

29 

50 

20 

30 

60 

53 

31 

30 

90 

32 

40 

53 

33 

60 

60 

34 

80 

53 

35 

80 

53 

36 

30 

53 

37 

60 

60 

30 


HARRY  MILES  JOHNSON 


is  evidently  present  here,  and  the  experimenter  was  unwilling 
to  accept  these  negative  results  as  conclusive  until  the  tests 
had  been  made  under  such  conditions  as  would  compel  the 
animal  to  make  her  choice  very  soon  after  the  stimulus  is 
presented. 

From  these  preliminary  experiments  it  becomes  evident  that 
in  order  to  reach  reliable  results  in  the  field  of  pitch-discrimina- 
tion new  apparatus  must  be  constructed  and  such  conditions 
fulfilled  as  will  enable  the  experimenter  to  exclude  certain 
vitiating  factors  inherent  in  tests  like  my  first  ones,  and  of 
the  Kalischer  and  Rothmann  type.  An  enumeration  of  these 
defects,  with  apparatus  proposed  for  their  elimination,  is  set 
forth  in  the  section  next  following. 

THE  CONDITIONS  OF  A DECISIVE  EXPERIMENT  ON  PITCH-DISCRIMIN- 
ATION IN  ANIMALS 

It  is  probably  evident  that  neither  in  the  results  of  my  own 
preliminary  experiments  nor  in  the  work  of  the  other  investi- 
gators which  has  been  discussed,  can  we  be  at  all  sure  that  the 
dogs  were  reacting  only  to  auditory  stimuli.  Some  obvious 
secondary  cues  have  to  be  eliminated  from  the  experimental 
conditions  if  results  of  future  experiments  are  to  be  reliable. 
It  seems  worth  while  to  mention  these  disturbing  factors,  some 
of  which  others  have  previously  pointed  out  in  describing  dis- 
crimination-experiments of  other  kinds. 

i.  11  Unconscious  helps U By  this  term  is  meant  any  sort  of 
body-movements,  which  the  animal  can  learn  to  associate  with 
a definite  reaction.  Those  likely  to  be  made  by  the  experi- 
menter under  such  conditions  as  Kalischer ’s  and  Swift’s,  or  by 
the  assistant  in  Rothmann ’s  experiment — namely,  such  nascent 
movements  of  the  arms  and  body  as  would  accompany  readiness 
to  strike  or  to  step  back  to  allow  the  dog  to  obtain  food,  are 
particularly  vicious,  as  appears  in  the  “Clever  Hans”  report. 
They  can  be  detected  visually  by  many  animals.  But  visually 
sensed  aids  by  no  means  exhaust  the  list.  Suppose  the  operator 
has  been  in  the  habit  of  recalling  the  dog  when  a wrong  choice 
is  made,  or  of  scolding  him  if  he  fails  to  inhibit,  and  encourag- 
ing him  by  a word  if  he  is  timid  in  reacting,  when  the  problem 
is  like  Kalischer ’s  and  Rothmann’s;  a very  slight  change  in 


HABIT  FORMATION  IN  THE  DOG 


31 


breathing  will  be  noticed  even  by  a blind  animal.  There  are 
other  movements  of  like  kind,  which  serve  as  auditory  stimuli. 
Now,  there  is  only  one  reliable  means  of  preventing  disturb- 
ance from  these  sources : Not  only  the  experimenter  but  all  others 
should  be  outside  the  room  in  which  the  animal  is  working . Roth- 
mann’s  Diener  or  any  bystander  can  disturb  the  dog  as  much 
as  could  the  experimenter,  and  indeed  is  more  likely  to  do  so, 
as  the  experimenter  if  he  is  honest  is  apt  to  take  greater  pains 
to  be  on  his  guard.  Meeting  this  condition  does  not  preclude 
the  experimenter’s  putting  the  animal  through  the  proper  reac- 
tions in  the  first  two  or  three  days’  work,  although  it  is  doubt- 
ful if  this  is  desirable ; but  as  soon  as  the  animal  is  left  to  dis- 
criminate, the  experimenter  should  leave  the  experiment  room. 
In  control  tests,  even  though  he  be  in  another  room,  it  is  highly 
expedient  that  the  experimenter  should  not  watch  the  animal 
while  making  his  choice , but  wait  until  the  choice  is  made.  This 
will  prevent  the  animals  being  given  any  auditory  “unconscious 
helps.”  In  my  later  work  I observed  this  precaution,  with 
satisfactory  results. 

2.  The  order  of  the  presentation  of  stimuli.  This  must  be 
varied  irregularly.  In  a given  series  of  say  ioo  presentations, 
the  animal  should  be  given  50  of  each.  In  actual  training  work, 
I have  found,  as  have  also  Yerk^s,  Watson  and  others,  that  it 
is  usually  unsafe  to  give  the  same  stimulus  more  than  three 
times  in  succession,  as  a position  preference  is  apt  to  become 
established.  In  control  tests,  after  the  animal  has  really  learned 
to  discriminate,  the  number  of  successive  presentations  of  the 
same  stimulus  can  be  safely  increased.  The  best  method  I 
have  used  in  training  work  for  determining  the  order  of  presen- 
tation is  the  use  of  a well  shuffled  pack  of  cards ; allowing  those 
of  one  color  to  represent  one  stimulus,  and  those  of  the  other 
color  the  other  stimulus.  If  more  than  three  cards  of  the  same 
color  appear  in  succession  the  extra  ones  can  be  laid  aside  until 
needed  to  break  into  an  overlong  series  of  the  other  color,  or 
until  the  bottom  of  the  pack  has  been  reached.  This  method 
assures  the  variation  being  irregular,  and  eliminates  the  possi- 
bility of  the  animal’s  successful  reaction  merely  to  the  order 
of  presentation.  The  probability  of  the  coincidence  of  an  order 
so  determined  with  the  animal’s  established  preference,  is  ex- 
tremely slight.  As  has  been  suggested  above,  the  experimenter 


32 


HARRY  MILES  JOHNSON 


making  up  an  order  of  presentation  at  random  may  too  easily 
fall  into  a rhythm  of  his  own. 

3.  Duration  of  the  stimulus.  This  should  be  made  as  nearly  the 
same  for  both  stimuli  as  possible.  If  the  animal  reacts  quickly 
the  stimulus  tone  may  be  sounded  until  choice  has  been  made ; if 
he  reacts  slowly,  however,  the  chances  are  that  he  will  disre- 
gard the  stimulus  if  its  duration  is  much  more  than  one  or  two 
seconds.  This  may  work  injury  if  the  animal  habitually  “sets 
himself”  to  react  when  the  stimulus  has  ceased — as  some  ani- 
mals will  do.  If  two  tones  widely  different  in  pitch  are  used, 
the  tendency  of  the  higher  one  to  die  away  more  quickly  than 
the  deeper,  may  be  a disturbing  element ; if  the  animal  reacts 
slowly,  both  tones  should  be  damped  at  the  end  of  the  time 
allowed,  regardless  of  the  animal’s  behavior. 


T 


U 0 

Figure  1— A,  home-box;  B,  introductory  alley;  C,  opening  into  alleys  D and 
D';  E,  E',  alleys  entering  food-compartments  F and  F';  G,  G',  punishment 
grills;  T,  table  containing  stimulus-forks.  V,  W,  X,  X',  Y and  Y'  are  doors, 
automatically  swinging  in  the  direction  indicated.  The  experimenter’s  place 
is  in  an  adjacent  room  by  window  O in  front  of  door  V of  the  home-box. 


HABIT  FORMATION  IN  THE  DOG 


33 


4.  Position  of  the  animal  when  the  stimulus  is  given.  This 
should  also  be  the  same  for  all  stimuli — or  as  nearly  the  same 
as  is  possible.  I have  already  referred  to  a control-test  of  my 
own  which  illustrates  the  value  of  this  precaution.  This  condi- 
tion may  be  met  by  the  use  of  the  stimulus-cage  which  I have 
devised,  a cut  of  which  appears  on  page  32.  The  explanation 
of  the  sketch  is  as  follows : A is  the  home-box,  4'  x 4',  in  which 
the  animal  is  placed  between  stimuli,  entrance  being  made  from 
without  by  the  door  V ; B is  an  introductory  alley,  6'  long  and 
2'  wide,  leading  to  the  alleys  D and  D'.  These  alleys  are  each 
1 o'  long  and  open  to  alleys  E and  E',  which  are  shut  off  by  the 
two  doors  X and  X'.  These  doors,  as  appears  in  the  cut,  are 
made  to  open  from  the  animal,  and  are  closed  automatically 
by  a small  coiled  spring.  Each  is  provided  with  an  iron  lift 
latch,  which  should  be  heavy  enough  to  catch  when  the  door 
is  closed  without  attention  from  the  operator.  A string  is  fast- 
ened in  a small  hole  drilled  in  the  end  of  the  lever  of  each  of 
these  latches,  and  run  through  an  eye-screw  in  the  door  above, 
then  through  a pulley  attached  to  the  side  of  alley  E or  E'  as 
the  case  may  be,  then  to  the  operator’s  place,  so  that  by  pulling 
the  string  the  door  may  be  unlatched  and  pulled  open  without 
the  operator’s  leaving  his  place.  When  the  string  is  released 
the  door  closes  and  latches  itself.  Alleys  E and  E'  open  into 
two  food-compartments  F and  F'.  The  covering  of  these  boxes 
is  provided  with  two  doors,  located  near  the  end  of  alleys  E 
and  E',  through  which  food  is  dropped.  Y and  Y'  are  two  doors 
opening  from  food-compartments  F and  F'  into  the  home-box 
A.  These  doors  are  not  provided  with  latches,  as  they  close 
behind  the  animal,  flush  with  the  jambs,  and  cannot  be  opened 
by  an  animal  which  has  not  free  use  of  its  hands,  such  as  has  the 
monkey,  raccoon,  or  the  squirrel.  They  are  provided  with  coiled 
springs,  like  those  on  doors  X and  X'.  My  animals  would  usually 
open  these  doors  from  the  food-compartments,  merely  pushing 
their  way  into  the  home-box,  but  it  is  well  to  provide  a means 
of  opening  them  with  strings  as  are  doors  X and  X',  for  the 
sake  of  timid  animals.  Door  W is  opened  by  means  of  a spring, 
as  doors  X,  X',  Y and  Y'  are  closed.  A heavy  gut  cord  is  fast- 
ened to  an  eye-screw  near  the  top  of  door  W,  and  run  through 
a small  hole  near  the  top  of  the  outside  frame -work  of  home-box 
A,  to  the  operator’s  station,  where  it  is  hooked  until  door  W 


34 


HARRY  MILES  JOHNSON 


is  to  be  released.  G and  G'  are  two  punishment-grills — strips 
of  brass  about  3'  long,  secured  to  a white  pine  board  3'  x 2'. 
Alternate  strips  are  connected  with  the  respective  poles 
of  the  secondary  coil  of  an  inductorium,  leaving  the  other 
end  free.  When  the  current  is  switched  in,  the  animal’s 
foot  must  rest  on  two  or  more  of  these  strips,  which  are 
only  1 cm.  wide  and  1 cm.  apart,  thus  completing  the  circuit 
and  causing  the  animal  to  receive  a shock.  The  induc- 
torium should  be  placed  outside  the  room  in  which  the  animal 
is  being  worked,  and  far  enough  away  that  the  sparking  noise 
will  not  disturb  the  experiment.  The  current  may  be  shifted 
through  G or  G'  by  a double-throw  switch  at  the  operator’s 
station.  My  experience  showed  that  in  a cage  of  this  size  the 
grills  G and  G'  should  be  made  longer  than  three  feet ; six  feet 
would  be  much  better.  Some  of  the  dogs  used  in  these  experi- 
ments would  jump  over  the  grill  when  they  were  shocked,  in- 
stead of  turning  back.  They  probably  would  not  have  persisted 
in  this  attempt  had  the  distance  been  greater.  As  it  was,  addi- 
tional rods  had  to  be  run  from  side  to  side  of  alleys  D and  D', 
above  the  grills,  so  that  the  dogs  could  not  jump  over  them  and 
escape  punishment. 

The  frame-work  of  this  cage  is  constructed  of  yellow  pine, 
1"  x 3";  the  top  and  sides  are  covered  with  woven  steel  wire, 
having  a mesh  about  1 cm.  square.  Food  is  kept  in  both  the 
food-compartments  F and  F'.  The  animal  is  given  the  problem 
of  choosing  a turn  to  the  left  into  alley  D,  leading  to  food- 
compartment  F,  at  one  tone,  and  a turn  to  the  right  into  alley 
D',  leading  to  food-box  F',  at  the  other  tone.  The  stimulus- 
tone  may  be  struck  while  the  animal  is  in  the  home-box  A,  and 
the  animal  released  after  it  has  been  damped;  or  the  tone  may 
be  sounded  after  the  animal’s  release,  say  one -half  second  before 
he  can  reach  the  end  of  the  introductory  alley.  If  punishment 
is  to  be  administered,  the  animal  receives  it  instantly  he  makes 
the  wrong  turn. 

In  a part  of  the  writer’s  experiments  presently,  to  be  des- 
cribed the  experimenter  sat  at  a table  about  four  feet  from 
door  V of  the  home-box.  When  the  animals  should  have  begun 
to  discriminate  a screen  could  be  interposed  between  the  table 
and  the  cage  to  conceal  the  operator.  Later  the  entire  appa- 


HABIT  FORMATION  IN  THE  DOG 


35 


ratus  was  moved  into  another  room,  and  the  experimenter  re- 
mained entirely  outside  the  animal-room  until  after  the  animal 
had  reacted  and  been  admitted  to  the  proper  food-box.  The 
animal  was  observed  through  the  center  window  shown  in  Fig.  i. 

Besides  the  elimination  of  the  secondary  criteria  mentioned 
above,  it  is  also  desirable  to  eliminate  another  possible  source 
of  disturbance,  namely  the  lapse  of  attention  which  may  ensue 
if  the  animal’s  reaction  is  delayed.  This  may  be  accomplished 
by  giving  the  stimulus  very  shortly — say  within  a second, 
before  the  animal’s  choice  is  to  be  made.  The  optimal  time 
may  vary  with  different  animals,  but  it  should  be  possible  to 
control  it.  In  using  the  stimulus-cage  described  above  the 
stimulus  may  be  presented  at  any  time  desired  before  the  ani- 
mal reaches  the  turn  into  alleys  D and  D'. 

The  criterion  of  discrimination  should  not  be  less  than  a 
perfect  record,  maintained  through  at  least  three  days.  The 
arbitrary  standard  of  95  perfect  trials  in  the  last  100,  which 
some  investigators  of  other  kinds  of  discrimination  have 
adopted,  may  be  allowable ; but  certainly  a poorer  record 
will  not  suffice.  The  higher  standard  is  preferable  to  this. 

The  final  condition  which  must  be  fulfilled  is  the  control- 
lability of  the  stimulus.  It  is  well  known  that  musical  tones 
differ  not  only  in  pitch,  but  also  in  intensity,  timbre,  non-musical 
concomitant  noise,  and  perhaps  in  localization.  These  other 
characteristics  must  be  controlled  if  we  are  to  make  the  assump- 
tion legitimately  that  the  subject  is  discriminating  on  the  basis 
of  pitch  alone.  In  addition  to  this  desideratum,  it  is  also  desir- 
able that  the  conditions  under  which  one  experimenter  works 
may  be  reproducible  by  another,  that  results  may  be  comparable. 

At  the  present  time  no  satisfactory  means  is  known  of 
measuring  the  intensity  of  sound.  It  may  be  varied  quite 
widely,  however,  in  electrically  actuated  tuning  forks  and  in 
blown  pipes  and  bottle  whistles;  the  latter  vary  in  pitch  with 
the  quantity  of  air  admitted.  The  method  of  varying  the  inten- 
sity of  the  stimulus  in  forks  will  be  described  later  in  this  section. 

The  best  means  of  controlling  timbre  is  by  the  use  of  instru- 
ments which  will  give  tones  as  nearly  pure  as  possible.  Reed 
instruments  cannot  be  controlled  in  this  respect.  Tuning  forks 
weakly  actuated  give  tones  as  nearly  pure  as  can  be  had,  al- 
though even  in  these  a high  anharmonic  partial  can  usually 


36 


HARRY  MILES  JOHNSON 


be  detected.  -Weakly  blown  pipes  or  bottle  whistles  are  perhaps 
the  next  best.  If  nearly  pure  tones  cannot  be  obtained,  the  next 
best  plan  is  to  have  the  tone  of  the  same  fundamental  pitch 
sounded  now  on  one  pipe  or  bottle -whistle,  now  on  another 
which  is  larger  or  smaller  than  the  first.  Thus  tones  of  the 
same  pitch  but  of  quite  different  timbre  can  be  produced.  If 
the  animal,  after  being  trained  to  a tone  on  one  instrument, 
shows  disturbance  when  another  instrument  giving  the  same 
tone  is  substituted,  it  is  safe  to  say  that  he  was  not  reacting 
merely  to  the  pitch  of  the  tones,  and  that  other  characteristics 
were  more  or  less  prominent. 

The  same  may  be  said  of  non-musical  concomitant  noise.  A 
struck  fork  gives  a peculiar  “cluck,”  which  is  rarely  the  same 
in  any  two ; a bowed  string  may  have  a peculiar  scrape  which 
lends  individuality  to'  it ; a blown  pipe  or  whistle  always  gives 
a whisper,  which  may  be  a part  of  its  individuality;  while  the 
rattle  of  no  two  reeds  is  perhaps  exactly  the  same. 

A tone  comparatively  pure  cannot  be  localized  correctly  in  a 
closed  room  because  of  standing  waves ; its  apparent  localization 
shifts  with  the  observer’s  position.  Angell27  asserts  that  it  can- 
not be  localized  even  in  the  open  air.  If  pure  tones  cannot  be 
made,  the  position  of  the  stimulus  instruments  should  be  fre- 
quently changed  in  control  tests . High  overtones  and  non-musical 
concomitant  noises  may  be  localized  quite  easily  by  an  animal, 
and  serve  as  the  basis  of  • discrimination. 

Of  instruments  which  will  fulfill  these  conditions,  one’s  choice 
is  limited  to  tuning  forks  and  blown  pipes  or  bottle-whistles, 
preference  being  by  far  on  the  side  of  the  first.  A reed  instru- 
ment, such  as  the  harmonium  or  the  mouth-harmonica,  which 
Kalischer  used,  does  not  admit  of  control  of  timbre,  nor  of  satis- 
factory control  of  intensity,  and  the  accessory  noise  is  consider- 
able. Trumpets,  which  were  used  by  Swift,  are  not  certain  in 
pitch,  and  the  timbre  varies  greatly  with  the  pitch  and  intensity 
of  the  tone  sounded. 

If  blown  pipes  or  whistles  are  used  they  should  be  easily 
tunable,  as  the  daily  change  in  temperature  and  density  of  the 
air  affects  their  pitch  considerably.  Differential  organ  pipes 
are  fairly  satisfactory.  The  Stern  variators  also  meet  this 

27  Angell,  J.  R.  Localization  of  tone.  University  of  Chicago  decennial 
publications,  Chicago,  1900. 


HABIT  FORMATION  IN  THE  DOG 


37 


requirement.  The  vernier  scales  and  the  card-board  index 
glued  on  the  dials  of  the  variators,  however,  are  useless  and 
should  not  be  relied  on.  There  is  wide  difference  between  the 
marks  on  the  scale  and  the  actual  pitches  under  variable  atmos- 
pheric conditions;  and  the  play  of  the  cogs  in  the  device  for 
raising  and  lowering  the  piston,  is  in  some  cases  greater  than 
three  points  on  the  scale. 

If  pipes  or  whistles  are  blown  from  an  ordinary  Stern  or 
Whipple  tank  they  are  not  accurate  in  pitch  within  a limit  of 
about  3'%  in  either  direction,  as  the  air  pressure  is  not  .con- 
stant. For  preliminary  or  rough  work  they  are  often  hseful 
when  blown  in  this  way,  but  should  not  be  depended  on  for 
finer  work.  The  Stern  tank  is  much  too  small.  It  will  not  blow 
a large  whistle  or  a c-256  d.v.  pipe.  The  air  is  so  quickly  ex- 
hausted that  if  it  is  in  the  same  room  with  the  animal,  the  noise 
of  raising  it  is  often  disturbing.  If  chords  are  blown  on  varia- 
tors blown  from  it,  it  requires  filling  after  nearly  every  stim- 
ulus. For  finer  work  Watson  28  has  devised  and  installed 
in  the  psychological  laboratory  at  the  Johns  Hopkins  Univer- 
sity an  air-system  consisting  of  a tank  filled  by  a motor-driven 
positive  pressure  blower.  The  tank  supplies  air-streams  from 
a distant  room.  The  pressure  is  remarkably  constant,  and 
makes  possible  an  accuracy  of  pitch  in  blown  pipes  or  whistles 
far  beyond  that  hitherto  attainable.  The  apparatus  is  rather 
expensive. 

The  apparatus  adopted  for  finer  discrimination  work  of  this 
kind  is  a system  of  “ tandem-driven  ’ ’ tuning  forks  similar  to 
that  recommended  and  used  by  Helmholtz  29.  In  the  present 
tests  the  apparatus  was  arranged  as  follows:  A c-64  d. V.  fork 
is  mounted  in  a room  100  feet  distant  from  the  experimental 
room  for  electric  actuation.  A diagram  of  this  fork  and  its 
equipment  is  shown  in  Fig.  2.  The  electrical  connection  is  as 
follows:  From  the  positive  pole  of  a six  volt  two  ampere  stor- 
age cell  to  a rhebstat,  thence  to  the  pole  a,  through  the  fork 
and  platinum  contact  p with  the  mercury  cup  c,  to  the  magnet 
m,  to  the  pole  b,  to  the  negative  pole  of  the  storage  cell.  Thus 
with  each  vibration  of  the  fork  the  current  is  made  and  broken 
at  the  contact  p with  the  mercury  cup  c.  The  mercury  in  c 


28  Watson,  John  B.  Article  as  yet  unpublished. 

29  Helmholtz,  H..  v.  Sensations  of  Tone  (Ellis’  translation). 


38 


HARRY  MILES  JOHNSON 


is  kept  covered  with  alcohol,  and  a secondary  circuit  through 
a condenser  is  made,  by  connecting  at  pole  a and  the  mercury 
cup  c.  This  is  to  eliminate  the  noise  of  sparking. 

In  the  experiment -room,  on  a table,  T,  about  six  feet  from 
the  end  of  alley  B of  the  stimulus-cage  shown  in  Fig  i,  are 
placed  the  stimulus-forks.  A diagram  of  one  is  shown  with  its 
mounting  in  Fig.  3.  The  ones  mounted  for  this  work  are  c-256 
d.v.,  e-320  d.  v.,  g-384  d.v.  and  c-512  d.v.  As  will  be  seen  these 
vibration -rates  are  all  simple  multiples  of  that  of  the  primary 
fork.  The  stimulus -forks  are  not  provided  with  contacts  but 
are  mounted  with  magnets  between  the  prongs.  The  current 
through  these  magnets  is  made  and  broken  at  each  complete 
vibration  of  the  primary  fork,  and  the  impulse  thus  given  is 
sufficient  to  actuate  the  stimulus  forks.  The  wiring  is  as  fol- 


Figure  2 — A,  B,  binding  posts;  C,  insulated  mercury  cup;  P,  P',  platinum  con- 
tacts; M,  magnet. 


lows:  From  the  positive  pole  of  a four  volt  six  amperes  storage 
cell  to  contact  a on  the  mounting  of  the  primary  fork,  through 
the  fork  and  platinum  contact  p'  to  a second  mercury  cup  not 
shown  in  the  cut  of  the  primary  fork,  but  which  is  separated 
and  insulated  from  mercury  cup  c by  hard  rubber  mounting; 
thence  to  a rheostat,  through  the  magnet  coil  between  the 
prongs  of  the  stimulus-fork,  to  a double -throw  switch  at  the 
table  at  the  experimenter’s  station;  thence  to  the  negative 
pole  of  the  storage  cell.  The  primary  fork  is  kept  going  through- 
out the  daily  series;  and  the  experimenter  has  only  to  turn 
the  double-throw  switch  to  cause  either  of  the  two  stimulus- 
tones  to  sound. 

Above  the  stimulus-fork  shown  in  Fig.  3 will  be  noticed  a 
Konig  resonator.  This  mediates  only  the  pure  tone  of  the 
stimulus-fork.  It  is  kept  in  place  by  a sleeve  which  is  fastened 
to  the  upright  rod  on  the  fork’s  stand.  A tone  of  maximum 
intensity  is  obtained  when  the  resonator  opening  is  about  1 mm 
from  the  ends  of  the  prongs  of  the  fork.  The  intensity  can  be 


HABIT  FORMATION  IN  THE  DOG 


39 


F,  standard  fork;  R,  Konig  resonator;  C,  clamp;  S,  set  screw;  P,  pillar  support- 
ing R;  A,  B,  screw  contacts;  M,  magnet,  supported  by  nut,  N,  sliding 
through  groove  G in  back  wall. 

varied  widely  by  varying  the  distance  between  the  resonator 
and  fork.  A vernier  scale  may  be  placed  on  the  sleeve  and  the 


40 


HARRY  MILES  JOHNSON 


rod,  which  shows  this  distance  accurately.  Then  if  the  amount 
of  current  passing  through  the  magnet  of  the  stimulus-fork  be 
known  and  the  distance  of  the  resonator  from  the  fork  be  also 
known,  it  will  be  possible  to  duplicate  these  conditions  and 
convert  these  readings  into  absolute  units  of  intensity  in  case 
a means  of  measuring  it  satisfactorily  should  ever  be  perfected. 

If  a wooden  resonance  case  is  used  instead  of  the  Konig  or 
Helmholtz  resonator,  results  are  not  so  satisfactory.  Intensity 
can  indeed  be  varied  by  varying  the  amount  of  current  passing 
through  the  magnet  of  the  stimulus-fork,  but  if  the  current  used 
be  strong,  overtones  become  quite  prominent.  Besides  the 
fundamental  tone  of  the  fork,  there  are  also  present  a high 
anharmonic  partial  and  an  undertone  of  the  pitch  of  the  primary 
fork.  The  latter  is  caused  by  periodic  increases  in  amplitude 
of  vibration  of  the  secondary  fork,  which  synchronize  with  the 
vibration  of  the  primary  fork,  due  to  the  impulse  of  the  current 
made  and  broken  by  the  primary.  This  undertone,  however, 
seems  to  be  mediated  by  the  wood  of  the  table  and  of  the  reso- 
nance case.  If  the  latter  be  removed  and  a Konig  resonator 
substituted  for  it,  and  if  the  stand  on  which  the  stimulus-fork 
is  mounted  be  padded  heavily  with  cotton  batting,  then  this 
undertone  is  not  detectible  by  the  human  subject,  even  with 
the  aid  of  a resonator.  Under  the  same  conditions  the  high 
partial  cannot  be  heard  by  the  best  human  observers  at  a dis- 
tance exceeding  two  feet,  so  it  probably  does  not  work  much 
disturbance.  No  overtones  can  be  detected  by  use  of  the  ordi- 
nary resonators.  The  maximum  intensity  of  the  fundamental 
is  very  great. 

By  this  means  may  be  obtained  a tone  which  is  practically 
pure,  of  widely  variable  if  not  measurable  intensity,  incapable 
of  being  localized  by  the  human  subject  at  least,  and  free  from 
accessory  noise. 

Through  the  use  of  such  a system  and  the  stimulus-cage 
described  above,  I believe  that  it  is  possible  to  meet  all  the 
conditions  of  reliable  tests  on  pitch-discrimination  in  animals 
which  I have  enumerated  above:  the  elimination  of  unconscious 
helps;  the  elimination  of  the  “delayed  reaction”  factor;  the 
use  of  a decisive  criterion  of  discrimination;  and  the  control- 
ability  cf  the  stimulus. 


HABIT  FORMATION  IN  THE  DOG 


41 


FURTHER  EXPERIMENTS  ON  TONAL  DISCRIMINATION  WITH 
IMPROVED  APPARATUS 

In  the  fall  of  1911,  the  experiments  on  pitch-discrimination 
were  continued  in  the  Johns  Hopkins  laboratory,  with  the  im- 
provement in  method  just  suggested.  The  two  tones  to  be 
discriminated  remained  c-256  d.v.  and  e-320  d.v.  They  were 
sounded  on  “tandem-driven”  forks  mounted  with  'Kong  reso- 
• nators,  as  described  above.  The  reaction  to  the  c-fork  was  a 
turn  to  the  left  at  the  end  of  alley  B,  and  the  choice  of  food- 
compartment  F;  that  to  the  e-fork,  a turn  to  the  right  and 
choice  of  food-compartment  F'.  The  experiments  had  to  be 
conducted  at  night — from  10  to  2 o’clock,  when  a quiet  build- 
ing could  be  had.  In  addition  to  Dogs  1 and  2,  two  normal 
female  puppies,  littered  June  1,  1911,  of  which  Dog  2 was  the 
dam,  were  introduced  as  a control.  These  animals  are  referred 
to  hereafter  as  Dogs  3 and  4. 

The  first  two  or  three  days  of  work  was  spent  in  feeding  the 
animals  in  the  stimulus-cage,  and  getting  them  accustomed  to 
passing  through  the  doors  without  hesitation.  After  they  had 
become  apparently  “at  home”  in  the  new  environment,  each 
animal  was  “put  through”  the  proper  reactions  to  the  two 
tones  for  three  series  of  fifteen  trials  each,  and  then  left  to  work 
out  the  problem  for  herself.  Punishment  was  not  introduced 
until  the  twenty-first  day  of  training.  The  results  were  not 
satisfactory.  The  animal’s  reactions  were  greatly  retarded  in 
every  case,  and  a certain  disturbance  resulted  which  none  of 
the  animals  entirely  overcame.  A shock  too  weak  to  be  dis- 
agreeable or  even  to  be  perceived  when  applied  to  the  human 
subject’s  dry  hand,  would  often  cause  great  disturbance  in  an 
animal  which  had  ignored  it  for  several  series.  Care  was  always 
taken,  too,  to  weaken  the  current  still  more  if  the  dogs’  feet 
were  wet.30 

For  several  weeks  Dog  1 would  go  to  grill  G',  mount  with 
the  left  foot  the  sill  on  her  right,  and  reaching  under  the  left 
fore-leg  with  her  right  forepaw,  would  scratch  the  grill  vigor- 
ously for  as  long  as  five  minutes,  sometimes,  barking  furiously 
all  the  while.  The  stimulus-tone  was  being  sounded  continu- 
ously— or  at  intervals  of  one  second  from  the  time  she  was 

30  Breed,  in  his  work  on  vision  in  the  chick  minimized  changes  in  shock  con- 
ditions by  having  the  floor  of  the  home-box  covered  with  moistened  material  so 
that  the  animals’  feet  were  always  wet.  This  precaution  seems  well  taken. 


42 


HARRY  MILES  JOHNSON 


released  from  the  home-box.  After  prolonging  this  behavior, 
she  would  suddenly  proceed  or  turn  back  and  choose  the  oppo- 
site alley.  Strange  to  say,  some  of  her  best  “accuracy”  records 
were  made  during  behavior  of  this  kind.  Dogs  3 and  4 insisted 
on  leaping  over  both  grills  from  the  beginning — even  before 
punishment  was  introduced.  Later,  rods  were  thrust  through 
the  meshes  of  the  wire  forming  the  sides  of  the  alley,  which  com- 
pelled these  dogs  to  creep  under  them  and  walk  across  the  grills. 
Both  these  animals  usually  consumed  some  minutes  in  hesita- 
tion before  choosing,  after  punishment  was  introduced,  and 

TABLE  6 

Discrimination  Between  c-256  d.v.  and  e-320  d.v.  Sounded  on  Tandem- 
driven  Forks  in  Standard  Cage 


Dog  1 

Dog  2 

Dog  3 

Dog  4 

Day 

% Accuracy 

% Accuracy 

% Accuracy 

% Accuracy 

1 

20 

67 

20 

60 

2 

30 

70 

00 

40 

3 

30 

50 

70 

70 

4 

20 

30 

70 

50 

5 

10 

70 

30 

50 

6 

30 

40 

60 

40 

7 

20 

70 

50 

40 

8 

20 

70 

30 

60 

9 

70 

40 

20 

50 

10 

30 

50 

20 

20 

11 

60 

47 

60 

53 

12 

40 

70 

30 

30 

13 

40  ' 

60 

60 

40 

14 

20 

30 

30 

40 

15 

40 

60 

30 

50 

16 

40 

60 

40 

60 

17 

70 

90 

30 

70 

18 

80 

50 

30 

60 

19 

60 

60 

50 

10 

20 

47 

53 

30 

30 

21 

53 

66 

33 

73 

22 

53 

60 

53 

53 

23 

67 

67 

40 

47 

24 

60 

67 

40 

47 

25 

40 

73 

50 

70 

26 

20 

53 

50 

73 

27 

33 

33 

50 

60 

28 

60 

40 

40 

10 

29 

40 

33 

47 

67 

30 

33 

60 

20 

53 

31 

60 

67 

60 

46 

32 

73 

60 

53 

47 

33 

80 

33 

40 

53 

34 

47 

40 

80 

40 

35 

80 

66 

33 

47 

36 

50 

46 

53 

80 

Day 

37 

38 

39 

40 

41 

42 

43 

44 

45 

46 

47 

48 

49 

50 

51 

52 

53 

54 

55 

56 

57 

58 

59 

60 

61 

62 

63 

64 

65 

66 

67 

68 

69 

70 

71 

72 

73 

74 

75 

76 

77 

78 

79 

80 

81 

82 

83 

84 

85 

86 

87 

88 

89 

90 

91 

92 


HABIT  FORMATION  IN  THE  DOG 
TABLE  6 — Continued 


Dog  1 

Dog  2 

% Accuracy 

% Accuracy 

66 

46 

40 

40 

60 

53 

53 

53 

53 

60 

53 

53 

73 

60 

67 

73 

67 

60 

53 

60 

40 

73 

73 

67 

73 

53 

73 

47 

60 

67 

47 

53 

47 

53 

33 

40 

47 

33 

53 

26 

47 

47 

33 

20 

33 

53 

47 

47 

67 

33 

60 

33 

80 

40 

60 

46 

53 

20 

47 

53 

60 

53 

80 

60 

80 

47 

67 

53 

40 

47 

40 

73 

40 

60 

67 

47 

60 

40 

60 

47 

60 

53 

67 

60 

47 

40 

60 

40 

53 

73 

47 

60 

80 

53 

47 

40 

80 

53 

60 

53 

60 

60 

67 

47 

80 

60 

47 

60 

67 

53 

60 

53 

Dog  3 

Dog  4 

% Accuracy 

% Accuracy 

73 

53 

40 

40 

53 

67 

60 

46 

53 

47 

40 

60 

80 

40 

60 

60 

60 

47 

80 

60 

53 

47 

47 

47 

67 

53 

53 

53 

40 

53 

73 

47 

40 

73 

40 

66 

33 

60 

53 

23 

47 

33 

47 

80 

53 

80 

67 

60 

47 

40 

73 

40 

73 

73 

80 

73 

60 

67 

53 

67 

80 

53 

60 

60 

60 

40 

80 

60 

47 

40 

53 

53 

60 

67 

40 

73 

80 

73 

53 

40 

40 

60 

40 

67 

60 

47 

53 

47 

67 

53 

73 

47 

60 

47 

53 

47 

73 

73 

40 

53 

40 

47 

47 

73 

53 

60 

80 

40 

73 

40 

53 

10 

43 


44 


HARRY  MILES  JOHNSON 


Dog  3 developed  a variety  of  position  habits.  After  perhaps 
three  weeks  both  became  accustomed  to  conditions  so  that 
they  did  not  hesitate  in  choosing  the  alley  to  a food-box;  but 
neither  could  be  made  to  turn  back  immediately  a shock  was 
received.  Both  would  proceed  to  door  X or  X'  as  the  case 
might  be,  or  cross  the  grill  at  least,  before  turning  and  going  to 
the  proper  place.  Dog  2 was  little  affected  by  punishment. 

The  learning  records,  showing  percentage  of  daily  accuracy, 
for  ninety-two  days  of  this  work  are  shown  in  table  6.  Not 
only  was  the  problem  not  learned  in  that  time,  but  no  animal 
showed  promise  of  improvement. 

In  the  belief  that  the  two  tones  may  have  been  so  nearly 
alike  that  the  dogs  could  not  discriminate,  the  experiment  was 
abandoned  for  the  time,  and  the  animals  were  given  the  prob- 
lem of  associating  release  from  the  home-box  at  the  stimulus- 
tone  c-256  d.v.  with  food  in  food-compartment  F,  and  release 
from  the  home-box  without  a stimulus-tone  with  food  in  food- 
compartment  F'.  Ten  days  (150  trials)  was  allotted  for  this 
work.  There  was  no  change  in  the  dogs’  behavior  after  the 
problem  had  been  changed,  beyond,  a return  for  one  or  two 
days  to  old  position-habits  which  had  been  abandoned.  At 
the  end  of  ten  days,  as  appears  in  the  learning  table  below, 
discrimination  was  not  established,  nor  was  any  improvement 
shown  by  any  animal.  This  was  taken  as  indication  that  the 
animals  had  been  disregarding  the  stimulus-tones  entirely.  The 
results  of  this  experiment  are  shown  in  table  7. 

TABLE  7 

Discrimination  Between  c-256  and  No  tone 


Dog  1 

Dog  2 

Dog  3 

Dog  4 

Day 

% 

% 

% 

% 

Accuracy 

Accuracy 

Accuracy 

Accuracy 

1 

40 

40 

60 

53 

2 

53 

47 

60 

53 

3 

67 

60 

47 

47 

4 

53 

53 

60 

47 

5 

60 

53 

47 

60 

6 

47 

47 

40 

50 

7 

67 

53 

20 

00 

8 

40 

40 

60 

60 

9 

47 

40 

47 

60 

10 

40 

67 

53 

67 

The  explanation  of  these  unexpected  results  is  not  easy.  It 
is  of  course  possible  that  in  ordinary  noises  the  dog  is  stimulated 


HABIT  FORMATION  IN  THE  DOG 


45 


only  by  the  high  overtones,  which  in  tones  as  nearly  pure  as 
those  sounded  on  this  apparatus,  may  have  been  lacking  or  so 
faint  as  not  to  be  effective.  There  is  of  course,  no  proof  of  this 
but  the  point  may  be  found  worthy  of  future  tests.  These  are 
not  practicable  at  the  present  time, 

It  has  been  suggested  by  a critic  that  the  stimulus  chosen — 
a pure  tone — is  one  so  different  from  those  stimuli  to  which  the 
animal  is  provided  with  some  form  of  instinctive  response,  that 
the  animal  should  not  be  expected  to  learn  readily  to  respond 
to  it.  Inasmuch  as  a pure  tone  cannot  be  localized,  there  may 
be  some  force  to  this  suggestion.  It  seems  to  the  casual  observer 
at  least  that  most  of  the  auditory  stimuli  which  affect  the  dog 
are  significant  because  they  are  noises  which  can  be  localized 
and  quickly  associated  with  the  things  making  them.  However, 
admitting  this  point,  the  fact  remains  that  it  is  useless  to  try  to 
test  any  theory  of  localization  of  the  center  for  pitch  by  experi- 
menting on  the  dog,  unless  the  animal  can  be  made  to  discrim- 
inate on  the  basis  of  pitch-difference  alone.  This  fact  can  be 
established  only  by  the  use  of  pure  tones  as  stimuli,  and  by 
working  under  some  such  conditions  as  are  proposed  above  as 
a standard.  It  is  also  open  to  question  whether  discrimination 
could  not  yet  be  established  if  by  proper  means  the  animal 
could  be  made  to  receive  the  stimuli. 

The  suggestion  was  also  made  that  in  the  stimulus -cage  the 
animal  is  in  a “highly  artificial”  situation,  and  reacts  under 
emotional  constraint.  This  point  is  made  much  of  by  Shepherd, 
also,  in  his  discussion  of  experiments  in  vision  31 . 

The  truth  of  the  first  half  of  this  suggestion  is  of  course  patent. 
Any  experiment  made  under  conditions  of  sensory  control  is 
necessarily  “artificial.”  The  animal  which  turns  at  the  flutter 
of  a bird  in  the  leaves  is  probably  affected  by  visual,  olfactory 
and  possibly  still  other  stimuli  than  auditory.  These  stimuli 
taken  together  with  the  sound  form  the  “situation”  in  which 
the  animal  is,  and  are  readily  associated  with  the  response, 
which  is  more  or  less  instinctive.  The  additional  auditory  stim- 
ulus may  be  only  a “contributing  agent,”  which  makes  the 
action  of  the  others  effective.  The  animal  may  be  compared  to 
the  subject  in  a reaction-time  experiment,  prepared  to  react 

31  Shepherd,  W.  T.  Mental  processes  of  the  Rhesus  monkey.  Psychological 
Monographs , 1911. 


46 


HARRY  MILES  JOHNSON 


when  the  click  or  flash  comes;  and  if  we  may  speak  for  the 
moment  in  terms  of  consciousness,  the  degree  of  “attention” 
to  the  auditory  stimulus  itself  is  minimal.  In  the  stimulus - 
cage,  however,  since  the  choice  of  reaction  must  be  made  on 
the  basis  of  a single  characteristic  of  the  tone,  the  demands  on 
his  “attention” — at  least  until  he  has  formed  many  new  asso- 
ciations— are  necessarily  much  greater  than  in  the  “natural” 
situation.  Accordingly  for  a time  at  least  his  behavior  should 
be  expected  to  be  quite  different  from  what  it  would  be  in  the 
“natural”  situation.  But  there  is  no  need  for  lamentation  over 
this  condition;  it  is  imposed  on  every  experimentor  in  sen- 
sation or  sensory  responses  in  which  results  are  to  be  trustworthy. 

As  to  the  other  half  of  this  suggestion — that  the  animal 
reacts  under  emotional  constraint — I do  not  feel  so  generous. 
Certainly  some  emotional  disturbance  attends  the  giving  of 
punishment  and  I am  by  no  means  convinced  that  in  working 
with  an  animal  as  highly  organized  as  is  the  dog,  it  is  desirable 
to  use  punishment.  But  once  the  animal  has  become  accus- 
tomed to  his  daily  work  the  signs  of  “emotional  constraint” 
are  few.  The  dogs  which  I have  used  are  always  eager  to  work ; 
the  excitement  which  attends  the  experience  probably  compen- 
sates in  large  measure  for  hunting  and  other  instinctive  reac- 
tions, which  the  animal  in  captivity  cannot  make.  My  dogs 
on  being  admitted  to  the  experimental  room  certainly  perform 
the  reactions  which  a hunting  dog  makes  when  presented  with 
a gun,  and  which  are  commonly  interpreted  as  “signs  of 
pleasure.”  32 

EXPERIMENTS  ON  DISCRIMINATION  BETWEEN  NOISES 

The  point  admitted  in  the  discussion  of  the  first  part  of  the 
last  mentioned  criticism,  may  seem  to  some  to  strengthen  a 
criticism  which  has  been  made:  namely,  that  there  is  a hiatus 

32 1 feel  that  it  is  hardly  necessary  to  consider  the  suggestion  which  has  been 
made,  that  the  dogs  which  I used,  being  mongrels,  should  be  expected  to  prove 
less  sensitive  to  pitch-difference  than  blooded  dogs;  and  further  that  acuity  of 
audition  varies  greatly  in  different  breeds.  This  certainly  is  Kalischer’s  report, 
but  as  has  been  shown  in  the  remarks  on  his  method,  this  result  is  no  more  reliable 
than  the  rest  which  he  reports,  as  it  is  not  evident  that  his  animals  were  reacting 
to  tone.  I know  of  no  other  data  offered  as  experimental  evidence.  But  admitting 
the  fact,  the  criticism  is  without  point  as  applied  to  this  work.  My  dogs  used  in 
the  preliminary  experiments  showed  the  same  apparent  discrimination  as  did 
Kalischer’s,  Rothmann’s  and  Swift’s;  perhaps  greater,  because  they  actually  made 
perfect  records  for  three  days  in  succession.  The  control  tests  indicate  that 
this  discrimination  was  only  apparent. 


HABIT  FORMATION  IN  THE  DOG 


47 


in  my  results;  that  the  discrimination  shown  by  the  animals 
in  the  preliminary  experiment  might  not  have  been  lost  had 
the  experimenter  gradually  effaced  himself.  In  other  words: 
It  may  be  too  much  to  expect  of  an  animal  that  he  form  the 
association  between  a sound  and  food  in  a certain  box  without 
some  helps  in  the  beginning  at  least;  although  he  may  be  able 
to  form  the  association  with  help  and  yet  retain  it  after  the 
helps  have  been  eliminated. 

It  is  manifest  that  the  justice  of  this  criticism  cannot  be  settled 
a priori.  Accordingly  it  seemed  well  to  determine  whether,  and 
if  so,  how  readily  an  animal  thrown  on  his  own  resources  can 
to  discriminate  between  auditory  stimuli  alone.  As  pure 
tones  were  clearly  out  of  the  question  for  the  time  being 
at  least,  it  was  decided  to  use  non-musical  noises,  which  might 
present  to  the  dog  differences  in  other  characteristics  than 
that  of  pitch. 

These  experiments  were  conducted  with  the  same  animals  and 
in  the  same  stimulus-cage  used  in  experiments  6 and  7.  It  had 
been  removed  meanwhile  to  a building  at  Homewood,  which 
was  more  quiet  than  the  one  in  the  business  section  of  the 
city  could  be.  The  experimenter  was  never  in  the  room  with 
the  animals  when  the  stimulus  was  given,  but  gave  it  from  the 
room  adjoining,  where  he  could  not  be  seen.  After  the  animal 
had  become  started  on  the  problem  the  experimenter  did  not 
even  watch  her  while  in  the  act  of  making  her  choice,  but  waited 
until  after  he  had  heard  her  cross  the  punishment  grill.  Thus 
the  question  of  “unconscious  helps’’  is  eliminated.  The  order 
of  presenting  the  stimulus  was  predetermined  by  the  use  of  a 
well  shuffled  pack  of  cards. 

The  stimulus -noises  were  sounded  on  two  ordinary  electric 
buzzers.  In  the  first  experiment,  designated  as  problem  8, 
one  buzzer  was  placed  over  each  of  the  two  doors  X and  X', 
but  were  merely  hung  over  the  edge  of  the  cage  by  their  flexible 
wire,  without  touching  the  cage  itself.  This  was  to  lessen  the 
probability  of  the  animals  reacting  to  vibration  of  the  cage. 
The  buzzers  were  actuated  by  current  from  two  ordinary  dry 
cells  connected  in  series ; the  current  being  made  by  the  operator 
pressing  a simple  contact  key.  Being  placed  over  the  entrance - 
doors  to  the  food-compartments,  they  could  be  easily  and  in- 


48 


HARRY  MILES  JOHNSON 


fallibly  localized  by  the  human  subject.  There  was  a notice- 
able difference  in  intensity,  that  of  buzzer  i,  placed  in  this 
experiment  over  door  X,  being  considerably  the  louder.  The 
quasi-tones  were  also  of  different  pitch,  that  of  buzzer  2,  over 
door  X',  being  near  the  third  of  buzzer  1.  This  selection  was 
made  deliberately.  The  timbre  of  the  two  respective  sounds 
also  differed.  The  sound  of  buzzer  1 was  decidedly  nasal,  while 
that  of  buzzer  2 was  quite  brilliant.  Since  these  conditions  un- 
fortunately are  not  reproducible  elsewhere  this  description  should 
suffice.  In  a word,  the  two  stimuli  differed  in  frequency,  am- 
plitude, form  and  direction  of  the  sound  waves. 

Contrary  to  the  method  employed  at  the  beginning  of  the 
experiments  on  tone -discrimination,  the  animals  in  this  experi- 
ment were  not  “put  through”  at  the  beginning,  but  left  to  form 
the  associations  between  a particular  sound  and  a particular 
food-box  for  themselves.  Punishment  was  not  given  in  case 
of  incorrect  choice.  Care  was  taken  to  make  the  duration  of 
each  stimulus  one-half  second,  or  as  near  one-half  second  as 
possible. 

The  problem  assigned  the  dogs  was  the  association  of  the 
sound  of  a given  buzzer  with  choice  of  the  food-compartment 
over  which  the  buzzer  was  placed.  For  the  first  two  days  after 
the  animals  were  introduced  to  the  problem  each  dog  tended 
to  react  negatively  to  the  stimulus.  This  was  followed,  except 
in  case  of  Dog  4,  by  a tendency  to  choose  food-compartment 
F'  regardless  of  the  stimulus  presented.  This  was  broken  up 
on  the  third  day  of  the  experiment  by  sounding  buzzer  1 a 
second  time  after  the  animal  had  wrongly  gone  into  alley  D'. 
After  only  two  or  three  repetitions  this  produced  a returning 
into  alley  D.  It  was  not  continued  after  this  day,  however, 
as  the  experimenter  feared  that  the  animal  might  make  it, 
rather  than  the  actual  sound  of  the  respective  buzzers,  the  cue 
for  reaction.  The  learning  tables,  which  follow,  reveal  a situa- 
tion quite  different  from  that  of  the  tone -discrimination  problem. 

This  experiment  shows  plainly  that  the  dog  can  learn  very 
quickly  and  without  help  to  discriminate  between  two  auditory 
stimuli.  The  question  remains  whether  the  discrimination  in 
this  case  was  on  the  basis  of  pitch,  intensity,  timbre  or  localiza- 
tion. During  the  experiment  the  animals  often  pricked  their 
ears  and  turned  their  heads  toward  the  sounding  buzzer,  so  it 


HABIT  FORMATION  IN  THE  DOG 


49 


TABLE  8 


Discrimination  Between  Buzzers 


Dog  1 

Dog  2 

Dog  3 

Dog  4 

Day 

% 

% 

% 

% 

Accuracy 

Accuracy 

Accuracy 

Accuracy 

1 

67 

47 

53 

47 

2 

60 

60 

47 

60 

3 

73 

87 

47 

80 

4 

87 

80 

73 

93 

5 

73 

100 

67 

93 

6 

87 

93 

80 

93 

7 

93 

100 

87 

100 

8 

87 

100 

100 

100 

9 

60  f 

100 

100 

100 

10 

100 

67* 

100 

11 

100 

100 

12 

100 

100 

seemed  evident  that  they  were  localizing  the  sound,  at  any 
rate.  It  seemed  well,  therefore,  to  ascertain  what  effect  inter- 
change of  the  buzzers  would  have  on  the  dogs’  reactions.  In 
this  control-experiment,  designated  as  problem  9,  buzzer  1 was 
placed  over  door  X'  and  buzzer  2 over  door  X.  The  sound  of 
buzzer  1 was  to  be  associated  with  food  in  compartment  F,  and 
that  of  buzzer  2,  with  food  in  compartment  F',  as  in  problem  8, 
just  learned.  The  difference  in  conditions  was  that  food  was 
now  to  be  obtained  in  the  compartment  opposite,  instead  of  at 
the  sounding  buzzer. 

Each  dog  was  continued  for  five  days  on  problem  8,  which 
had  been  learned  some  three  weeks  earlier.  The  animals  had 
done  no  work  meanwhile,  but  the  feeding  hour  had  remained 
the  same.  Each  animal  had  given  at  least  three  successive  days 
of  perfect  records  immediately  preceding  the  beginning  of  prob- 
lem 9.  The  first  day’s  record  of  each  animal  on  problem  9 
immediately  follows.  The  letters  R and  L signify  right  and 
left  compartments,  respectively. 

This  control  test  shows  quite  clearly  that  the  location  of  the 
source  of  sound  with  respect  to  food  is  the  characteristic  of 
the  stimulus  which  had  been  determining  the  animal’s  reac- 
tions. Each  dog  had  been  simply  going  to  the  compartment 

* The  problem  was  “learned”  on  the  ninth  day.  The  record  of  the  tenth  day 
is  of  a control-experiment,  described  on  page  53,  made  to  show  the  disturbing 
effect  of  variable  position  of  the  animal  when  the  stimulus  is  given. 

t The  animal’s  work  on  this  day  was  disturbed  by  the  falling  of  a heavy  door 
near  food-compartment  F while  the  series  was  in  progress.  For  the  remainder 
of  the  day  she  refused  to  choose  F under  any  conditions.  She  was  left  to  run  freely 
in  the  cage  all  night  in  order  to  overcome  the  disturbance. 


50  HARRY  MILES  JOHNSON 


Proper 

Actual  choice  by 

choice 

Dog  1 

Dog  2 

Dog  3 

Dog  4 

1 R 

L 

L 

L 

L 

2 L 

R 

R 

R 

R 

3 R 

L 

L 

L 

L 

4 L 

R 

R 

R 

R 

5 L 

R 

R 

R 

R 

6 R 

* 

L 

L 

L 

7 R 

* 

L 

L 

L 

8 L 

* 

* 

R 

R 

9 R 

L 

* 

* 

L 

10  R 

L 

* 

* 

L 

11  L 

R 

R 

* 

R 

12  R 

* 

L 

* 

L 

13  L 

t 

L 

* 

R 

14  R 

L 

* 

L 

15  R 

L 

* 

L 

over  which  a buzzer  had  sounded.  Dogs  i and  3 gave  up  after 
making  a few  reactions  of  this  kind;  Dog  2,  having  given  up 
the  problem  and  acquired  a new  interest,  relapsed  into  an 
ancient  position-habit;  while  Dog  4,  a very  active  half -grown 
puppy,  maintained  the  old  basis  of  choice  throughout  the  series 
without  reward.  The  following  table  shows  the  learning -record 
of  Dogs  1,  2 and  4.  Work  with  Dog  3 was  discontinued  after 
the  fourth  day,  as  at  that  time  she  attempted  to  escape  through 
the  door  in  the  top  of  food  compartment  F',  near  door  X',  and 
became  entangled  with  the  gut  cord  by  which  door  X'  is  opened. 
In  her  struggles  she  succeeded  in  wrecking  some  apparatus  and 
was  so  disturbed  by  the  experience  that  for  three  successive 
days  she  refused  to  leave  the  home-box. 

TABLE  9 

Discrimination  Between  Buzzers,  Their  Positions  Having  Been  Inter- 
changed After  Discrimination  had  Become  Established 


Dog  1 

Dog  2 

Dog  4 

Day 

% Accuracy 

% Accuracy 

% Accuracy 

1 

00 

07 

•00 

2 

27 

33 

20 

3 

20 

53 

53 

4 

60 

60 

67 

5 

80 

53 

87 

6 

73 

73 

100 

7 

80 

87 

ICO 

8 

93 

93 

10c 

9 

93 

100 

10 

100 

100 

11 

100 

100 

12 

100 

* Refused  to  work, 
f Removed. 


HABIT  FORMATION  IN  THE  DOG 


51 


These  results  show  nothing  new  except  for  the  record  of  the 
first  day.  There  may  be  some  significance  in  a comparison  of 
the  records  of  Dogs  i and  2 with  that  of  Dog  4.  Both  the  older 
dogs  required  a longer  time  to  overcome  the  habit  formed  in 
problem  8 although  the  time  for  learning  problem  8 was  as 
short  for  Dog  2 as  for  the  younger  animal. 

At  this  point  the  experiments  had  to  be  abandoned.  I think 
it  well,  however,  to  outline  the  program  which  it  was  my  inten- 
tion to  carry  out  had  conditions  permitted,  as  I believe  it  a 
safe  approach  to  an  investigation  of  pitch-discrimination.  First, 
it  was  proposed  to  have  the  animals  form  the  simple  association 
required  under  the  conditions  of  problem  8.  Then,  as  a new 
problem,  let  the  two  buzzers  be  brought  nearer  and  nearer 
together,  until  they  shall  be  together  on  the  table  near  the  end 
of  the  introductory  alley  B.  If  the  animals  can  still  discrimi- 
nate, the  characteristic  of  localization  is  eliminated.  Then  let 
a stimulus  fork  be  substituted  for  one  buzzer,  and  if  discrimina- 
tion can  be  established  and  maintained  between  the  two  sounds, 
substitute  the  second  stimulus-fork  for  the  other  buzzer.  If 
the  animals  learn  to  discriminate  between  the  two  tones,  varia- 
tions of  intensity  and  other  controls  can  follow.  Discrimina- 
tion between  noises  lies  well  within  the  dog’s  capacity.  It  may 
yet  be  possible  to  obtain  reliable  evidence  of  discrimination  on 
the  basis  of  pitch-difference  if  the  animal  can  be  brought  grad- 
ually to  the  point  where  it  will  be  affected  by  the  stimulus. 

SUMMARY 

The  foregoing  experiments  have  failed  in  showing  to  what 
extent  the  dog  is  sensitive  to  difference  of  pitch.  They  have 
not  established  that  he  is  sensitive  to  pitch-difference  at  all. 
While  they  have  not  proved  the  contrary,  they  should  have 
shown  that  we  are  not  safe  in  accepting  the  assertion  of  Kal- 
ischer,  Rothmann  and  Swift,  that  the  dog  has  an  exceedingly 
fine  absolute  pitch  sensitivity.  These  experiments  have  shown 
that  the  evidence  submitted  to  date  does  not  warrant  such  a 
conclusion.  They  have  also  shown  some  of  the  difficulties  in 
the  way  of  making  satisfactory  tests  on  audition  in  animals, 
and  should  have  demonstrated  what  is  and  what  is  not  a reli- 
able method  of  investigation  in  this  field.  It  should  also  be 


52 


HARRY  MILES  JOHNSON 


apparent  that  in  using  animals  for  operations  to  settle  questions 
of  cerebral  localization,  it  is  necessary  to  use  methods  of  train- 
ing far  more  complicated  than  many  physiologists  appear  to 
appreciate.  Certainly  the  remarkable  variation  in  the  findings 
of  the  investigators  whose  work  has  been  considered  in  the 
foregoing  pages,  may  be  readily  explained  by  reference  to  their 
methods  of  training. 


APPENDIX  I 

On  page  5 the  reader  was  referred  to  a daily  record  made 
by  one  of  my  animals  on  pitch-discrimination  which  is  repro- 
duced below. 


Problem  6,  Dog  3,  December  14,  1911 


Trial 

Proper  choice 

Actual  choice 

1 

R 

R 

2 

L 

L 

3 

R 

R 

4 

L 

L 

5 

R 

R 

6 

R 

L 

7 

R 

R 

8 

L 

L 

9 

R 

R 

10 

L 

L 

11 

L 

R 

12 

R 

L 

13 

R 

R 

14 

L 

L 

15 

R 

R 

Correct  reactions 

. . . . 12 

Incorrect  reactions 

Total 

....  3 

. . . . 15 

Percentage  of  accuracy . 

. . . . 80 

Even  superficial  inspection  will  show  that  this  animal  was 
merely  choosing  the  right  and  the  left  food-compartments  alter- 
nately regardless  of  the  stimulus  given.  She  developed  much 
more  elaborate  position-habits  than  this.  This  record  is  shown 
merely  to  call  attention  to  the  necessity  of  having  several  con- 
secutive perfect  daily  records,  with  the  order  of  presentation 
and  secondary  criteria  under  control,  before  assuming  that  the 
animal  has  learned  to  discriminate. 


HABIT  FORMATION  IN  THE  DOG 


53 


APPENDIX  II 

CONTROL  EXPERIMENT  ON  DISCRIMINATION  TO  NOISE,  AFTER 

LEARNING 

In  commenting  on  Rothmann’s  experiment  (page  14)  I em- 
phasized the  desirability  of  having  all  stimuli  presented  when 
the  animal  is  occupying  the  same  position  relative  to  the  food. 
The  following  record  is  more  spectacular  than  some  others 
which  my  animals  have  made,  but  I have  noted  numerous  other 
instances  which  illustrate  the  point  almost  as  well. 

It  has  already  been  said  that  this  dog  had  learned  the  prob- 
lem. On  the  second  day  of  her  tra’ning  she  showed  an  nvariable 
tendency  to  turn  to  the  right  food-compartment  (F')-  Each  time 
on  the  second  day  and  twice  on  the  third  day,  immediately  after 
the  animal  had  made  the  wrong  turn,  the  experimenter  sounded 
the  left  buzzer  the  second  t me.  When  the  control-test  was 
made,  eight  days  had  elapsed  since  this  had  been  done.  This 
day’s  record,  which  follows,  showTs  clearly  how  strong  and 
persistent  was  the  association. 


Problem  8,  Dog  2,  April  22,  1912 


Trial 

Proper  choice 

Actual  choice 

1 

R 

Rt 

2 

R 

Rf 

3 

L 

L 

4 

R 

Rf 

5 

L 

L 

6 

L 

L 

7 

R 

L* 

8 

L 

L 

9 

R 

L* 

10 

R 

L* 

11 

R 

L* 

12 

L 

L 

13 

R 

L* 

14 

R 

Rf 

15 

L 

L 

Correct  reactions 

. . . . 10 

Incorrect  reactions 

Total 

5 

. . . . 15 

Percentage  of  accuracy . 

. . . . 66§ 

* Turned  R;  operator  sounded  (r)  buzzer  again;  dog  reversed  choice, 
t Stimulus  presented  only  once. 


II.  COMPARISON  OF  LEARNING-TIME  AND  LEARNING-METHODS 
IN  BLIND  AND  IN  NORMAL  DOGS 


The  behavior  of  the  two  temporarily  blind  dogs  used  in  the 
experiments  already  described  suggested  another  problem  for 
which  the  animals  could  be  used  as  material.  It  is  evident  that 
an  animal  trained  to  open  the  “puzzle-box”  used  by  Thorn- 
dike 1 in  work  with  cats  and  other  animals  and  by  Watson 2 
and  others  in  experiments  on  the  white  rat,  must  make  a 
complicated  and  delicate  adjustment  in  a minimal  time.  It 
should  be  interesting  to  ascertain  to  what  extent  the  dog  makes 
use  of  vision  in  making  this  adjustment;  and  to  compare  the 
methods  employed  by  blind  and  by  normal*  dogs  in  learning 
such  problem.  Further,  these  dogs  had  learned  to  behave  in 
their  ordinary  environment  practically  as  normal  dogs,  although 
none  of  their  “spatial  world”  was  “visual  space.”  The  “Moly- 
neaux  problem”  is  at  once  suggested,  and  it  becomes  of  interest 
to  note  any  changes  in  behavior  concurring  with  the  formation 
of  a world  of  visual  space. 

Six  food-boxes  were  constructed  for  this  problem  of  2"  x 2" 
white  pine  framework  covered  with  steel  woven  wire  having  a 
mesh  about  1 cm.  square.  These  boxes  were  each  30"  wide, 
24"  long  and  24"  high.  A door  12"  x 12"  was  cut  in  one  of 
the  30"  x 24"  sides,  and  hung  so  as  to  be  opened  by  a coiled 
spring  when  the  latch  was  released.  A sketch  of  one  of  these  boxes 
is  shown  in  Figure  4.  The  boxes  will  hereafter  be  referred 
to  by  number.  The  kind  of  latch  and  hanging  of  the  door  to 
each  box  is  shown  below. 


Box  No. 
1 
2 

3 

4 

5 

6 


Kind  of  latch 
spoon-dip 
turn-button 
lift-bar 
slide-bar 
peg-in-hole 
bobbin-string 


Door  opening 
inward 
outward 

a 


u 

inward 


The  program  was  to  have  each  dog  while  yet  blind  learn  a 
separate  set  of  three  boxes;  then  to  note  what  disturbance,  if 
any,  followed  total  darkening  of  the  room  in  which  the  work 

1 Thorndike,  E.  L.  Animal  Intelligence. 

2 Watson,  John  B.  Animal  Education. 

54 


HABIT  FORMATION  IN  THE  DOG 


55 


had  been  learned;  to  note  disturbances  resulting  from  turning 
the  boxes  90°,  180°  and  270°  respectively  from  the  first  posi- 
tion ; and  to  make  a retention-test  after  sixty  days  of  rest.  The 
dog’s  eyes  were  then  to  be  opened.  After  recovery  they  were 
to  be  given  their  old  problem  boxes,  for  the  purpose  of  noting 
any  change  in  method  that  might  take  place;  then  each  dog 
was  to  be  made  to  learn  the  three  problem-boxes  which  the 
other  dog  had  learned  while  blind.  The  last  part  of  this  test 
was  not  carried  out  on  Dogs  1 and  2,  since  neither  showed 
enough  evidence  of  vision  to  warrant  the  continuation  of  the 
experiment. 


As  to  the  animals  used,  Dogs  1 and  2,  the  temporarily  blind 
females  used  in  the  work  on  audition,  have  already  been  de- 
scribed on  p.  20.  Dog  5 was  a male  of  mixed  breed — a cross  be- 
tween the  bull-terrier  and  the  black-and-tan — and  was  unusually 
quick,  active  and  strong.  He  performed  many  tricks,  among 
them  jumping,  catching  a ball,  etc.,  with  great  skill.  Dogs 
6,  7 and  8 were  the  offspring  of  Dog  5 and  Dog  2.  They  were  all 
males,  littered  June  1,  1911,  in  the  psychological  laboratory 
of  the  University  of  Chicago.  Dog  6 was  normal  and  cowardly. 


56 


HARRY  MILES  JOHNSON 


Dogs  7 and  8 were  rendered  temporarily  blind  by  the  same 
method  as  that  used  on  Dogs  i and  2.  Dr.  Henry  Dick,  of  the 
department  of  pathology  of  the  University  of  Chicago,  kindly 
performed  the  operation  when  the  puppies  were  seven  days  old. 
Dog  7 was  unusually  large,  but  not  clumsy.  Despite  his  blind- 
ness he  was  able  by  reason  of  his  fierceness  and  strength  to 
maintain  leadership  of  the  eight  dogs  with  which  he  was  allowed 
to  run.  Dog  8 was  small  and  decidedly  of  the  terrier  type. 
He  was  rather  timid  among  the  other  dogs,  and  even  in  the 
laboratory  his  movements  were  deliberate.  It  should  be  said, 
however,  that  all  the  animals  took  readily  to  training  of  this 


Figure  5 — Floor  plan  of  experimental-room.  C,  cages  F,  problem-box  contain- 
ing food;  GD,  glass  exit  door;  WD,  wooden  entrance  door;  dotted  line,  habit- 
ual path  of  animal.  Experimenter’s  station,  outside  room,  by  GD. 

kind.  They  were  fed  once  a day — during  the  daily  test.  Imme- 
diately after  the  series  was  completed  for  the  day,  each  animal 
was  allowed  as  much  food  as  it  would  take.  All  the  animals 
were  in  excellent,  thrifty  condition  throughout  the  experimen- 
tation. 

Dogs  1 and  2 were  between  four  and  five  years  old  when  they 
were  introduced  to  this  problem.  Dog  5,  a stray,  was  about  one 
year  of  age.  Dogs  6,  7 and  8 were  five  and  one -half  months  old 
when  work  with  them  was  begun.  The  experiments  made  on 
Dogs  1,  2 and  5 were  between  November  5,  1910  and  March 
20,  1911.  Those  made  on  Dogs  6,  7 and  8 were  between  Novem- 
ber 15,  1911  and  July  12,  1912. 


HABIT  FORMATION  IN  THE  DOG 


57 


The  following  method  was  employed  in  training:  A room, 
the  floor-plan  of  which  is  shown  in  Fig.  4,  was  partitioned  off 
from  a larger  room,  from  which  the  observations  were  made 
The  problem-box  F was  placed  in  the  smaller  room,  sixteen 
feet  from  the  wooden  door  W.D.  in  the  diagram,  and  about 
four  feet  directly  opposite  the  glass  door  G.D.  where  the  operator 
stood.  Food  was  placed  in  the  problem-box,  the  door  of  which 
was  left  open  for  the  first  week.  The  animal  which  was  left  to 
run  free  in  the  larger  room,  was  admitted  through  the  wooden 
door  W.D.  to  the  smaller  room,  where  it  had  already  become 
accustomed  to  being  fed.  The  wooden  door  opened  by  the 
operator  pulling  a rope  running  from  it  to  the  glass  door,  and 
was  closed  by  a weight  and  pulley  system  after  the  animal 
had  passed  through.  After  the  animal  had  obtained  the  food 
in  the  problem-box,  it  was  released  from  the  smaller  room  into 
the  larger  through  the.  glass  door  G.D.  Food  was  again  placed 
in  the  problem-box  and  the  animal  readmitted  through  the 
wooden  door  as  before.  Every  animal  soon  acquired  a fixed 
path  to  and  from  the  problem-box,  which  path  is  indicated 
by  the  dotted  line  and  arrows  in  Fig.  4.  By  this  method  of 
training  previous  to  the  setting  of  the  problem  the  animal’s 
problem  was  simplified.  There  was  no  apparent  disturbance 
from  the  operator’s  movements:  as  soon  as  the  animal  was 
released  through  the  glass  door  G.D.  it  immediately  ran  to 
the  wooden  door  and  awaited  readmission  to  the  animal  room; 
it  was  out  of  sight  of  the  operator  and  wasted  no  time  in  trying 
to  get  food  in  other  than  the  prescribed  way.  When  the  animal 
was  presented  to  the  problem-box  the  operator  was  out  of  the 
room,  and  in  the  actual  experimentation,  out  of  sight  of  the 
animal,  as  the  larger  room  was  darkened  in  the  earlier  stages 
of  each  new  problem. 

This  general  mode  of  procedure — the  food-motive  and  the 
removal  of  the  operator  from  the  animal’s  immediate  presence — 
has  of  course  been  used  before  by  other  experimenters  and  on 
other  animals.  It  differs  from  the  method  of  Thorndike. 
In  his  work  the  animals  weie  confined  in  the  puzzle  box,  it 
being  assumed  that  the  animal’s  desire  to  escape  would  be  a 
satisfactory  motive  to  bring  about  the  opening  of  the  box. 
The  animals  were  dropped  into  the  box  from  the  top.  Some 
of  them  being  more  nervous  or  timid  than  others,  were  more 


58 


HARRY  MILES  JOHNSON 


greatly  disturbed  by  this  procedure ; some  apparently  became 
frantic ; the  movements  of  others  were  inhibited  probably 
from  “fright.”  Still  others,  more  quiet,  became  satisfied  after 
making  a few  unsuccessful  attempts  to  escape,  and  remained 
quiet  for  a long  time.  The  defects  n this  method  are  obvious, 
and  the  advantages  of  the  one  adopted  for  this  work  will  become 
more  apparent  when  the  animals’  behavior  is  discussed. 

After  the  animal  had  been  fed  from  the  open  box  for  a week 
or  more,  one  day’s  work  was  done  with  the  door  of  the  problem- 
box  wedged  open  by  only  about  two  inches  from  the  jamb. 
The  dog  had  to  force  it  open  in  some  way  in  order  to  get  the 
food.  This  was  found  necessary  in  the  preliminary  experiments 
because  the  animals  would  not  try  to  open  the  box  when  it 
was  latched.  After  sniffing  and  scratching  lightly  about  the 
corner  they  would  lie  down  for  hours.  This  behavior  lasted 
through  three  successive  days  and  the  experimenter  believed 
that  prolonging  the  animals’  hunger  could  produce  only  harm- 
ful results.  After  one  day  of  feeding  from  the  partly  closed 
box  every  animal  quickly  attacked  the  problem  of  opening  the 
latched  door. 

Time  was  taken  at  each  trial  after  the  box  was  first  latched. 
The  record  was  of  the  number  of  seconds  required  for  the  animal 
to  obtain  the  food  after  it  had  crossed  the  dotted  line  from  the 
glass  door  to  the  corner  of  the  problem-box.  This  point  was 
chosen  rather  than  the  wooden  door,  because  Dogs  i and  2 
were  much  heavier  and  slower  of  movement  than  any  of  the 
other  dogs,  and  required  one  to  two  seconds  more  time  to  reach 
the  problem-box  from  the  wooden  door,  although  their  move- 
ments in  opening  the  boxes  were  as  swift  and  as  accurate  as 
were  those  of  any  of  the  other  dogs.  There  was  one  disad- 
vantage, however,  in  that  it  was  difficult  to  tell  within  one-half 
second  or  so  when  the  dog  had  crossed  this  line  if  the  work 
was  done  in  total  darkness.  Time  was  taken  with  an  ordinary 
stop-watch.  This  records  to  0.2  seconds.  Fractional  readings 
less  than  0.5  seconds  were  disregarded;  those  greater  than 
0.5  second  were  counted  one  second.  Some  experimenters 
attempt  to  take  time-readings  in  this  way  as  closely  as  0.2 
seconds,  and  consider  the  fractions  at  full  value  in  computing 
their  results.  In  such  work  as  this,  however,  the  writer  be- 
lieves such  a record  shows  an  apparent  accuracy  which  is  not 
real.  The  experimenter’s  reaction-time  will  show  considerable 


HABIT  FORMATION  IN  THE  DOG 


59 


variation;  the  ordinary  cheap  laboratory  stop-watch  may 
show  a difference  of  0.2  second  in  the  time  necessary  to  start 
and  to  stop  it  respectively;  the  instrument  gets  out  of  order 
easily,  and  the  experimenter  does  not  react  to  a movement  of 
the  animal  which  is  absolutely  constant  for  any  two  reactions. 
Further  the  writer  does  not  believe  a difference  of  0.2  seconds 
to  be  significant  in  an  animal’s  making  so  complicated  a reac- 
tion as  that  of  opening  the  problem-box. 

In  the  experiments  on  Dogs  1,  2 and  5,  twenty  trials  a day 
were  allowed.  Dogs  6,  7 and  8 were  allowed  only  ten  daily 
trials.  It  will  be  seen  from  the  records  that  the  dogs  allowed 
only  ten  trials  a day  required  fewer  trials  and  in  some  cases 
even  fewer  days  than  did  the  animals  given  twenty  trials  under 
similar  conditions.  This  may  be  explainable  by  the  fact  that 
after  a certain  amount  of  work  has  been  done  an  animal  may 
tend  to  become  careless,  through  fatigue  perhaps,  and  will 
relapse  into  errors,  which,  becoming  habitual,  persist  for  a consider- 
able time.  The  tables  show  the  distribution  of  errors  made  in 
this  work  by  each  dog,  according  to  the  place  in  the  animal’s 
daily  series.  It  would  be  interesting  to  know  just  what  is  the 
optimal  number  of  daily  trials  which  should  be  allowed  to  a 
dog  as  compared  with  other  animals  in  order  to  economize  the 
learning  process  to  the  greatest  degree. 


Day.. 


Trials 

1 

2 

3 

4 

5 

6 

7 

8 
9 

10 

11 

12 

13 

14 

15 

16 

17 

18 

19 

20 


TABLE  1 

Learning  Records  on  Box  1 
Dog  1 (Blind  9 ) 
Problem  1 


1 2 3 4 5 6 7 8 


10  11  12  13  14  15  .16  17  18  19  20  21 


1 1 
1 1 
1 1 
1 1 
1 1 
1 1 
1 1 
1 1 
1 1 
1 1 
1 1 
1 1 
1 1 
1 1 
1 1 
1 1 
1 1 
1 1 1 
1 1 1 
1 1 1 


1 1 


1 
1 

1 1 
1 1 1 


1 1 


1 1 


1 1 1 


1 1 1 


1 1 


1 1 
1 1 


Total 

errors 

11 

12 

11 

10 

12 

11 

10 

11 

10 

12 

11 

11 

12 

11 

10 

10 

10 

10 

10 

11 


Total  errors  20  20  20  17  16  17  8 12  5 12  10  15  17  11  7 


0 0 


% Error. . . 100  100  100  85  80  85  40  60  25  60  50  75  85  55  35  30  10  5 0 0 0 

% Accuracy  0 0 0 15  20  15  60  40  75  40  50  25  15  45  65  70  90  95  100  100  100 

Av.  time 5.010.4  2.7  2.9  2.1  1.5  1.5  1.9  1.9  1.5  1.3  1.2  1.1  1.1  1.0  1.0  1.0 


216 


60 


HARRY  MILES  JOHNSON 


Days. 


Trials 

1 

2 

3 

4 

5 

6 

7 

8 
9 

10 

11 

12 

13 

14 

15 

16 

17 

18 

19 

20 


1 1 
1 1 


1 1 
1 1 
1 1 
1 1 
1 1 
1 1 
1 1 


TABLE  1 — Continued 
Learning  Records  on  Box  1 
Dog  5 (Normal  cT) 

, Problem  1 

5 6 7 8 9 10  11  12 


1 1 


Total 

errors 

5 

4 

4 

3 

4 

3 

4 

3 

4 

5 

5 
4 
8 
4 
4 

6 

4 

3 

5 

4 


Total  errors  20  20  20  12  8 2 2 


10  0 0 


% Error...  100  100  100  60  40  10 
% Accuracy  0 0 0 40  60  90 
A v.  time 20.0  5.0  1.5  1.1 


Days 

Trials 
■ 1 
2 

3 

4 

5 

6 

7 

8 
9 

10 


2 3 


10  5 5 0 0 0 
90  95  95  100  100  100 
1.0  1.0  1.0  1.0  1.0  10. 

Dog  6 (Normal  cT) 
Problem  2 

7 8 9 10  11  12  13  14 


1 1 1 
1 1 1 


1 1 1 
1 1 
1 


15  16  17  18  19  20  21  22  Total 

errors 

1 5 

7 

1 5 

1 3 

2 


Total  errors  84236334 


3242120321000  55 


% Error...  80  40  20  30  60  30 

% Accuracy  20  60  80  70  40  70 

Av.  time...  3.3  1.8  1.2  1.4  1.9  1.2 


Days. 


Trials 

1 

2 

3 

4 

5 

6 

7 

8 
9 

10 


1 2 3 4 5 6 7 


30  40  20  30  20  40  20  10 
70  60  80  70  80  60  80  90 
1.2  1.0  1.3  1.0  1.0  1.1  1.0  1.0 

Dog  7 (Blind  ) 

Problem  2 

8 9 10  11  12  13  14  15  16 


1*  1 1 
1 1 
1 


1 1 1 
1 1 1 
1 1 
1 1 1 
1 


1 1 1 


1 1 


1 1 1 


1 1 


1 1 
1 


1 1 


1 1 


1 1 


1 1 1 
1 1 


1 1 1 
1 1 1 
1111 
1111 


1 1 


20  0 30  20  10  0 0 0 

80  100  70  80  90  100  100  100 

1.2  1.0  1.0  1.1  1.0  1.0  1.0  1.0 


17  18  19  20  21  22  23  24  25  Total 
errors 


Total  errors  10  77553342 


3 4 8 


6 3 


3 0 2 1 0 0 0 95 


% Error...  100  70  70  50  50  30  30 

% Accuracy  0 30  30  50  50  70  70 

Av.  time...  4.6  6.5  3.1  1.3  1.9  1.6  1.3 


40  20  60  60  30  40  80  60  60 

60  80  40  40  70  60  20  40  40 

1.1  1.1  1.3  1.6  1.4  2.0  2.5  1.7  1.3 


30  10  30  0 20  10  0 0 0 

70  90  70100  80  90100100100 
1.3  1.1  1.2  1.0  1.0  1.1  1.0  1.0  1.0 


HABIT  FORMATION  IN  THE  DOG 


61 


TABLE  1 — Continued 
Learning  Record  on  Box  1 
Dog  8 (Blind  cT,  After  Operation) 
Problem  5 


Days 

1 

2 

3 

4 

5 

6 

7 

8 

9 

10 

11 

12 

13 

14 

15 

16  17 

Total 

lridis 

errors 

i 

1 

1 

1 

1 

1 

1 

1 

1 

8 

2 

1 

1 

1 

1 

1 

1 

1 

7 

3 

1 

1 

1 

1 

1 

1 

6 

4 

1 

1 

1 

1 

1 

1 

1 

1 

8 

5 

1 

1 

1 

1 

1 

1 

1 

7 

6 

1 

1 

1 

1 

1 

1 

1 

7 

7 

1 

1 

1 

1 

1 

1 

1 

1 

8 

8 

1 

1 

1 

1 

1 

1 

6 

9 

1 

1 

1 

1 

1 

1 

1 

7 

10 

1 

1 

1 

1 

1 

1 

1 

1 

1 

1 

10 

Total  errors 

9 

8 

7 

7 

5 

5 

7 

6 

3 

5 

6 

3 

2 

1 

0 

0 0 

74 

% Error. . . 

90 

80 

70 

70 

50 

50 

70 

60 

30 

50 

60 

30 

20 

10 

0 

0 0 

% Accuracy 

10 

20 

30 

30 

50 

50 

30 

40 

70 

50 

40 

70 

80 

90 

100  100  100 

Av.  time...  , 

...  18.0  5.1  4.2  3.1  3.5  2.4  2.6  2.0  2.1 

1.4  1 

.1 

1.2 

1.0  1.0  1.0 

Days 

Trials 

1 

2 

3 

4 

5 

TABLE  2 

Learning  Record  on  Box  2 
Dog  2 (Blind  9 ) 
Problem  2 

6 7 8 9 10  11  12  13  14  15 

16 

17  18  19  20 

Total 

errors 

1 

1 

1 

1 

1 

1 

1 

1 

1 

1 

1 

1 

1 

1 

13 

2 

1 

1 

1 

1 

1 

1 

1 

1 

1 

1 

1 

11 

3 

1 

1 

1 

1 

1 

1 

1 

1 

1 

1 

10 

4 

1 

1 

1 

1 

1 

1 

1 

1 

1 

1 

10 

5 

1 

1 

1 

1 

1 

1 

1 

1 

1 

1 

1 

11 

6 

1 

1 

1 

1 

1 

1 

1 

1 

1 

1 

10 

7 

1 

1 

1 

1 

1 

1 

1 

1 

1 

1 

1 

11 

8 

1 

1 

1 

1 

1 

1 

1 

1 

1 

1 

1 

1 

12 

9 

1 

1 

1 

1 

1 

1 

1 

1 

1 

1 

1 

11 

10 

1 

1 

1 

1 

1 

1 

1 

1 

1 

1 

10 

11 

1 

1 

1 

1 

1 

1 

1 

1 

8 

12 

1 

1 

1 

1 

1 

1 

1 

7 

13 

1 

1 

1 

1 

1 

1 

1 

1 

1 

1 

10 

14 

1 

1 

1 

1 

1 

1 

1 

1 

1 

1 

1 

11 

15 

1 

1 

1 

1 

1 

1 

1 

1 

1 

1 

1 

11 

16 

1 

1 

1 

1 

1 

1 

1 

1 

1 

1 

1 

1 

12 

17 

1 

1 

1 

1 

1 

1 

1 

1 

1 

1 

1 

1 

1 

13 

18 

1 

1 

1 

1 

1 

1 

1 

1 

1 

1 

1 

11 

19 

1 

1 

1 

1 

1 

1 

1 

1 

1 

1 

1 

1 

12 

20 

1 

1 

1 

1 

1 

1 

1 

1 

1 

1 

1 

1 

1 

13 

Total  errors  20 

20 

20 

20 

19 

19 

15 

16 

17 

11 

2 

8 

1 

12 

14 

2 

10  0 0 

217 

% Error...  100  100  100  100  95  95  75  80  85  55  10  40  5 60  70  10  5 0 0 0 

% Accuracy  0 0 0 0 5 5 25  20  15  45  90  60  95  40  30  90  95  100  100  100 

Av.  time...  3.3  2.6  3.4  3.2  3.1  2.7  2.1  2.3  1.2  1.8  1.3  1.6  1.6  1.6  2.3  1.6  1.1  1.2  1.1  1.0 


62 


HARRY  MILES  JOHNSON 


TABLE  2 — Continued 
Learning  Records  on  Box  2 
Dog  5 (Normal  cT) 
Problem  4 


Days.... 

Trials 

1 

2 

3 

4 

5 

6 

7 

8 
9 

10 

11 

12 

13 

14 

15 

16 

17 

18 

19 

20 


9 10  11  12  13  14 


% Error...  100  100 
% Accuracy  0 0 

Av.  time...  2.5  2.2 


Days 

Trials 

1 

2 

3 

4 

5 

6 

7 

8 
9 

10 


100  95  85  90 
0 5 15  10 

2.3  1.9  2.2  1.2 


3 4 5 6 


100  60  30  5 20  0 0 0 

0 40  70  95  80  100  100  100 

1.4  1.2  1.1  1.1  1.0  1.0  1.0  1.0 

Dog  6 (Normal  c^) 

Problem  5 

7 8 9 10  11  12  13  14  15 


1 

1 1 
1 1 
1 
1 
1 
1 


Total  errors  8 9 7 


1 1 


1110  0 0 


% Error...  80  90 
% Accuracy  20  10 
Av.  time...  3.0  4.1 


Days 1 

Trials 

1 


70  60  70  60 
30  40  30  40 
3.6  5.0  3.1  2.8 

Dog 


40  10  20  10  10  10  0 0 0 

60  90  80  90  90  90  100  100  100 

3.0  1.9  1.2  1.0  1.1  1.0  1.0  1.0  1.0 

7 (Blind  After  Operation) 

Problem  5 

7 8 9 10  11  12  13  14 


111111 
11111 
1 1 1 
1 1 1 

111111 


1 1 


1 1 


1 1 
1 1 1 
1 1 1 


1 1 


Total  errors  10  8 7 7 8 4 


% Error...  100  80 
% Accuracy  0 20 
Av.  time... 22.0  9.1 


70  70  80  40 
30  30  20  60 
4.7  3.9  3.1  2.2 


6 3 2 2 1 0 0 0 

60  30  20  20  10  0 0 0 

40  70  80  80  90  100  100  100 

2.6  2.0  1.7  1.4  1.5  1.0  1.1  1.0 


Total 


1 

1 

1 

1 

1 

1 

1 

1 

1 

errors 

9 

1 

1 

1 

1 

1 

1 

1 

1 

1 

9 

1 

1 

1 

1 

1 

1 

1 

1 

8 

1 

1 

1 

1 

1 

1 

1 

1 

8 

1 

1 

1 

1 

1 

1 

1 

1 

8 

1 

1 

1 

1 

1 

1 

1 

1 

1 9 

1 

1 

1 

1 

1 

1 

1 

1 

1 9 

1 

1 

1 

1 

1 

1 

1 

1 

8 

1 

1 

1 

1 

1 

1 

1 

1 

8 

1 

1 

1 

1 

1 

1 

1 

1 

8 

1 

1 

1 

1 

1 

1 

1 

7 

1 

1 

1 

1 

1 

1 

1 

1 

8 

1 

1 

1 

1 

1 

1 

6 

1 

1 

1 

1 

1 

1 

1 

7 

1 

1 

1 

1 

1 

1 

1 

7 

1 

1 

1 

1 

1 

1 

1 

7 

1 

1 

1 

1 

1 

1 

1 

1 

1 ' 9 

1 

1 

1 

1 

1 

1 

1 

1 8 

1 

1 

1 

1 

1 

1 

1 

7 

1 

1 

1 

1 

1 

1 

1 

7 

3 20 

20 

20 

19 

17 

18 

20 

12 

6 1 

4 0 0 0 157 

Total 

errors 

5 
7 
7 
2 

6 
6 
6 
5 

4 

5 

53 


Total 

errors 

7 

8 
6 

4 
8 

5 

5 

6 
5 
4 


58 


HABIT  FORMATION  IN  THE  DOG 


63 


Days 12  3 

Trials  

1 111 

2 1 1 

3 111 

4 111 

5 1 1 

6 1 

7 1 1 

8 1 1 

9 

10  1 1 


TABLE  2 — Continued 
Learning  Records  on  Box  2 
Dog  8 (Blind  cT) 
Problem  2 
4 5 6 7 8 9 10  11  12 

1 1 1 
1 
1 
1 

1 1 1 

1 

1 

1 1 
1 


Total 

errors 

6 

3 

4 

4 

5 
2 
3 
3 
2 
3 


Total  errors  767922101000  35 

% Error...  70  60  70  90  20  20  10  0 10  0 0 0 

% Accuracy  30  40  30  10  80  80  90  100  90  100  100  100 

Av.  time. ..72.0  2.1  6.3  8.0  2.2  1.8  1.9  1.4  1.1  1.0  1.0  1.0 


TABLE  3 

Learning  Records  on  Box  3 
Dog  1 (Blind  9 ) 
Problem  3 

Days 123456789 

Trials  — 

111  1 
2 11111 

3 111 

4 1 1 

5 111 

6 1 1 

7 1 1 

8 1 

9 1 

10  1 

11  1 

12  1 

13  1 

14  1 

15  1 1 

16  1 

17  1 

18  1 

19  1 

20  111 


Total  errors  16  85232000 

% Error...  80  40  25  10  15  10  0 0 0 

% Accuracy  20  60  75  90  85  90  100  100  100 

Av.  time...  — 7.5  1.2  1.4  1.1  1.1  1.1  1.0  1.0 


Total 

errors 

3 

5 

3 

2 

3 

2 

2 

1 

1 

1 

1 

1 

1 

2 

1 

1 

1 

1 

3 


36 


64 


HARRY  MILES  JOHNSON 


TABLE  3 — Continued 
Learning  Records  on  Box  3 


Dog  5 (Normal  cT  ) ^ j 

Problem  3 

Days 1 2 3 4 5 6 Total 

Trials  — — - — errors 

1 1 1 

2 11  2 

3 111  3 

4 11  2 

5 1 1 

6 1 1 

7 1 1 

8 1 1 

9 1 1 

10  1 1 

11  1 1 2 

12  1 1 

13  1 1 

14  1 1 

15  1 1 

16  1 1 

17  0 

18  0 

19  1 1 

20  0 


Total  errors  16  4 2 0 0 0 


% Error...  80  20  10  0 0 0 
% Accuracy  20  80  90  100  100  100 
Av.  time...  2.5  1.1  1.0  1.0  1.0  1.0 


Days 1 2 3 

Trials  

1 111 

2 111 

3 1 1 

4 1 

5 111 

6 1 1 

7 1 1 

8 111 

9 111 

10  111 


Dog  6 (Normal  cT) 
Problem  4 

4 5 6 7 8 9 10  11  12  13 


1 1 1 
1111  1 
1 1 

1 1 1 
1 1 1 
1111 
1 1 

1 

1 1 


22 


Total 
— errors 
6 
8 
4 
4 
6 
C 
4 

4 

5 
4 


Total  errors  9796653312000  51 

% Error...  90  70  90  60  60  50  30  30  10  20  0 0 0 

% Accuracy  10  30  10  40  40  50  70  70  90  80  100  100  100 

Av.  time...  2.5  1.7  1.4  1.4  1.2  1.3  1.5  1.1  1.3  1.0  1.0  1.0  1.0 


Dog  7 (Blind  cT  , After  Operation) 
Problem  4 


Days 

Trials  ■ 

1 

2 

3 

4 

5 

6 

7 

8 

9 

10 

11 

12 

13 

14 

15  16 

Total 

errors 

1 

1 

1 

1 

1 

1 

1 

1 

7 

2 

1 

1 

1 

1 

1 

1 

1 

7 

3 

1 

1 

1 

1 

1 

1 

1 

1 

8 

4 

1 

1 

1 

1 

1 

5 

5 

1 

1 

1 

1 

1 

1 

6 

6 

1 

1 

1 

1 

1 

1 

1 

7 

7 

1 

1 

1 

1 

1 

1 

1 

1 

1 

1 

10 

8 

1 

1 

1 

1 

1 

1 

6 

9 

1 

1 

1 

1 

1 

1 

6 

10 

1 

1 

1 

1 

1 

1 

. 1 

1 

8 

Total  errors 

I 8 

8 

6 

6 

6 

7 

4 

6 

5 

6 

2 

4 

2 

0 

0 0 

70 

% Error. . . 

. 80 

80 

60 

60 

60 

70 

40 

60 

50 

60 

20 

40 

20 

0 

0 0 

% Accuracy  20 

20 

40 

40 

40 

30 

60 

40 

50 

40 

80 

60 

80 

100 

100  100 

Av.  time... 

6.0  < 

3.1  3.4  3.1  3.3  1 

:.6  1 

[.2  1.4  1.2 

1.2 

1.0 

1.0  1.1 

1.0  1.0  1.0 

HABIT  FORMATION  IN  THE  DOG 


65 


TABLE  3 — Continued 
Learning  Records  on  Box  3 
Dog  8 (Blind  cT) 
Problem  1 


Days 

TViola 

1 

2 

3 

4 

5 

6 

7 

8 

9 

10 

11 

12  13  14 

15 

Total 

lnais 

errors 

1 

1 

1 

1 

1 

1 

1 

6 

2 

1 

1 

1 

1 

1 

5 

3 

1 

1 

1 

1 

1 

1 

6 

4 

1 

1 

1 

1 

1 

5 

5 

1 

1 

1 

1 

1 

1 

1 

7 

6 

1 

1 

1 

1 

1 

5 

7 

1 

1 

1 

1 

1 

1 

1 

1 

1 

9 

8 

1 

1 

1 

1 

1 

1 

1 

7 

9 

1 

1 

1 

1 

1 

1 

6 

' 10 

1 

1 

1 

1 

1 

1 

1 

1 

8 

Total  errors 

10 

10 

9 

9 

8 

6 

3 

5 

1 

1 

1 

1 0 0 

0 

64 

% Error. . . 

100  100 

90 

90 

80 

60 

30 

50 

10 

10 

10 

10  0 0 

0 

% Accuracy 

0 

0 

10 

10 

20 

40 

70 

50 

90 

90 

90 

90  100  100 

100 

Av.  time... 

— 

— 24.7  5.1  3.1  2.6  2.1 

2.1 

1.3 

1.5 

1.4  1.0  1.0  1.0 

1.0 

Days 1 

Trials 

1 


TABLE  4 

Learning  Records  on  Box  4 
Dog  2 (Blind  9 ) 

Problem  1 

7 8 9 10  11  12  13  14  15  16  17  18 


Total  errors  20  20  13  16  20  20  14  13  19  8 3 3 1 2 2 0 0 0 

% Error...  100  100  65  80  100  100  70  65  95  40  15  15  5 10  10  0 0 0 

% Accuracy  0 0 35  20  0 0 30  35  5 60  85  85  95  90  90  100  100  100 

Av.  time... 12.0  3.5  3.3  3.2  1.8  2.1  2.1  2.4  1.1  1.3  1.7  1.3  1.3  1.1  1.0  1.0 


Total 

errors 

11 

9 

10 


174 


66 


HARRY  MILES  JOHNSON 


Days 1 2 3 4 5 

Trials  

1 11111 

2 11111 

3 11  1 

4 1 11 

5 11  1 

6 11  1 

7 11  11 

8 1111 

9 1111 

10  11  1 

11  1111 

12  11111 

13  11111 

14  1111 

15  11111 

16  11111 

17  11111 

18  1 1 

19  111  1 

20  111 


TABLE  4 — Continued 
Learning  Records  on  Box  4 
Dog  5 (Normal  c?) 
Problem  2 
6 7 8 9 10  11 


1 1 1 
1 

1 

1 


1 

1 


1 

1 

1 1 


Total 

errors 

8 

6 

3 

4 
4 

3 

4 

4 

5 

3 

5 . 

5 

5 

5 

6 
7 
5 
2 

4 
3 


Total  errors  20  19  14  i7  9 9 1 2 0 0 0 91 

100  95  70  85  45  45  5 10  0 0 0 

0 5 30  15  55  55  95  90  100  100  100 

31.0  8.011.8  1.3  1.1  1.3  1.0  1.0  1.0 


% Error. . . 
% Accuracy 
Av.  time... 


Days 1 2 3 4 5 

Trials  

1 111 

2 11  11 

3 11111 

4 11  11 

5 11  1 

6 111  1 

7 11111 

8 11  11 

9 111  1 

10  1111 


Dog  6 (Normal  cT) 

Problem  1 

7 8 9 10  11  12  13  14  15  16117  18  19  20  21 


1 1 
1 1 


1 1 
1 1 


1111 


1 1 


1 1 1 


1 1 
1 1 


1 1 


1 1 
1 

1 1 
1 


Total 

errors 

13 

12 


11 

9 

13 

14 
12 
12 

8 


Total  errors  10  10  6688  10  95854681351000  113 


% Error...  100  100  60  60  80  80  100  90  50  80  50  40  60  80  10  30  50  10  0 0 0 

%’Accuracy  0 0 40  40  20  20  0 10  50  20  50  60  40  20  90  70  50  90  100  100  100 

Av.  time... 2.9  2.3  2.6  5.0  1.7  3.3  2.2  2.6  1.9  1.5  2.5  2.0  1.3  1.3  1.4  1.1  1.0  1.0  1.0 


Days 1 2 

Trials  

1 1 1 

2 1 1 

3 1 1 

4 1 1 

5 1 1 

6 1 1 

7 1 1 

8 1 1 

9 1 1 

10  1 1 


3 4 5 6 7 


11111 
11111 
111  1 
111  1 
111  1 
1 1 1 
1111 
111  1 
111  1 
1 1 1 


Dog  7 (Blind  cT) 

Problem  1 

8 9 10  11  12  13  14  15  16  17 


1 111 
11  11 
1 1 
1 1 
1 

1 1 
1 

1 1 
1 1 
1 1 


Tota 

errors 

11 

11 

8 

8 

7 

7 

7 

8 
8 
7 


Total  errors  10  10  999493733321000  82 

% Error...  100  100  90  90  90  40  90  30  70  30  30  30  20  10  0 0 0 

% Accuracy  0 0 10  10  10  60  10  70  30  70  70  70  80  90  100  100  100 

Av.  time... 22.8  3.4  3.8  2.7  4.4  2.6  2.3  1.9  1.2  1.7  1.3  1.1  1.0  1.0  1.0 


HABIT  FORMATION  IN  THE  DOG 


67 


TABLE  4 — Continued 
Learning  Records  on  Box  4 
Dog  8 (Blind  c After  Operation) 
Problem  4 


Days 

TViolci  _ 

1 

2 

3 

4 

5 

6 

7 

8 

9 

10 

11 

12 

13 

14 

Total 

i rials 

errors 

i 

1 

1 

1 

1 

1 

5 

2 

1 

1 

1 

1 

1 

1 

1 

7 

3 

1 

1 

1 

1 

1 

1 

6 

4 

1 

1 

1 

1 

1 

1 

6 

5 

1 

1 

1 

1 

4 

6 

1 

1 

1 

3 

7 

1 

1 

1 

3 

8 

1 

1 

1 

3 

9 

1 

1 

1 

1 

1 

5 

10 

1 

1 

1 

3 

Total  errors 

7 

8 

8 

6 

3 

5 

3 

2 

1 

1 

1 

0 

0 

0 

45 

% Error...  70  80  80  60  30  50  30  20  10  10  10  0 0 0 

% Accuracy  30  20  20  40  70  50  70  80  90  90  90  100  100  100 

Av.  time...  4.0  3.4  2.8  2.2  2.6  1.9  1.4  1.6  1.1  1.3  1.0  1.0  1.0  1.0 


TABLE  5 

Learning  Records  on  Box  5 
Dog  1 (Blind  $ ) 
Problem  2 


Days 1 2 3 4 5 6 7 8 9 10  11  12  13  14  15  16  17  18  19  Total 


XXlctlS 

errors 

1 

1 

1 

1 

1 

1 

1 

1 

1 

1 

1 

10 

2 

1 

1 

1 

1 

1 

1 

6 

3 

1 

1 

1 

1 

1 

1 

1 

1 

8 

4 

1 

1 

1 

1 

1 

1 

1 

1 

1 

1 

10 

5 

1 

1 

1 

1 

1 

1 

1 

1 

8 

6 

1 

1 

1 

1 

1 

5 

7 

1 

1 

1 

1 

[ 4 

8 

1 

1 

1 

1 

1 

1 

1 

7 

9 

1 

1 

1 

1 

4 

10 

1 

1 

1 

1 

1 

5 

11 

1 

1 

1 

1 

1 

1 

6 

12 

1 

1 

1 

1 

1 

1 

1 

1 

1 

1 

1 

11 

13 

1 

1 

1 

1 

1 

1 

1 1 

8 

14 

1 

1 

1 

1 

1 

1 

1 

1 

1 

9 

15 

1 

1 

1 

1 

1 

5 

16 

1 

1 

1 

1 

1 

1 

1 

7 

17 

1 

1 

1 

1 

1 

1 

1 

1 

1 

9 

18 

1 

1 

1 

1 

1 

1 

1 

7 

19 

1 

1 

1 

1 

1 

1 

1 

1 

1 

1 

1 

11 

20 

1 

1 

1 

1 

1 

1 

1 

1 

1 

1 

10 

Total  errors 

20 

20 

18 

14 

12 

7 

9 

10 

12 

11 

7 

4 2 

12  10  0 0 

150 

% Error...  100  100  90  70  60  35  45  50  60  55  35  20  10  5 10  5 0 0 0 

% Accuracy  0 0 10  30  40  65  55  50  40  45  65  80  90  95  90  95  100  100  100 

Av.  time 3.8  2.5  2.4  1.5  1.7  3.3  2.1  1.9  1.6  1.5  1.2  1.1  1.1  1.1  1.0  1.0  1.0 


68 


HARRY  MILES  JOHNSON 


TABLE  5 — Continued 
Learning  Records  on  Box  5 
Dog  5 (Normal  cT) 
Problem  5 


Days 

Trials  - 

1 

2 

3 

4 

5 

6 

7 8 9 10 

Total 

errors 

1 

1 

1 

1 

1 

4 , 

2 

1 

1 

1 

3 

3 

1 

1 

1 

1 

4 

4 

1 

1 

1 

3 

5 

1 

6 

1 

1 

1 

1 

4 

. 7 

1 

1 

1 

1 

4 

8 

1 

1 

1 

3 

9 

1 

1 

2 

10 

1 

1 

1 

3 

11 

1 

1 

1 

3 

12 

1 

1 

1 

3 

13 

1 

1 

1 

1 

1 

5 

14 

1 

1 

2 

15 

1 

1 

16 

1 

1 

1 

3 

17 

1 

1 

2 

18 

1 

19 

1 

1 

2 

20 

1 

1 

2 

Total  errors 

17 

16 

12 

5 

2 

1 

2 0 0 0 

55 

% Error. . . 

85 

80 

60 

25 

10 

5 

10  0 0 0 

% Accuracy  15 

20 

40 

75 

90 

95 

90  100  100  100 

Av.  time. . 

— 

3.3  2.5  2.0  1.2  1.2  1.0  1.0  1.0  1.0 

Dog  6 (Normal  cJ1) 

Problem  6 

Days 

1 

2 

3 

4 

5 

6 

7 8 9 10 

Total 

TViolc?  — 

1 rldlS 

— ■ errors 

1 

1 

1 

1 

1 

4 

2 

1 

1 

1 

3 

3 

1 

1 

2 

4 

1 

1 

5 

1 

1 

1 

3 

6 

1 

1 

1 

3 

7 

1 

1 

8 

1 

1 

1 

3 

9 

1 

1 

1 

3 

10 

1 

1 

Total  errors 

8 

7 

4 

2 

1 

0 

2 0 0 0 

24 

% Error... 

80 

70 

40 

20 

10 

0 

20  0 0 0 

% Accuracy  20 

30 

60 

80 

90  100 

80  100  100  100 

Av.  time... 

3.8  2.9  2.7  1 

1.6  1.1 

1.0  1.3  1.0  1.0  1.0 

Dog  7 (Blind  After  Operation) 

Problem  6 

Days 

1 

2 

3 

4 

5 

6 

7 8 9 10  11 

Total 

TV;  o lc» 

in  alS 

l 

1 

1 

1 

1 

1 

5 

2 • 

1 

1 

1 

1 

1 

1 

6 

3 

1 

1 

1 

3 

4 

1 

1 

1 

3 

5 

1 

1 

2 

6 

1 

1 

2 

7 

1 

1 

1 

1 

1 

5 

8 

1 

1 

1 

3 

9 

1 

1 

1 

3 

10 

1 

1 

1 

1 

4 

Total  errors  10  8742311000  36 


% Error...  100  80  70  40  20  30  10  10  0 0 0 

% Accuracy  0 20  30  60  80  70  90  90  100  100  100 

Av.  time 7.0  2.6  2.5  1.9  2.2  1.6  1.4  1.3  1.0 


HABIT  FORMATION  IN  THE  DOG 


69 


TABLE  5 — Continued 


Learning  Records  on  Box  5 
Dog  8 (Blind  (?) 
Problem  3 


Days 

Tri  olo  _ 

1 

2 

3 

4 

5 

6 

7 

8 

9 

10 

11 

12  13 

Total 

lnais 

1 

1 

1 

1 

1 

1 

1 

6 

2 

1 

1 

1 

1 

1 

5 

3 

1 

1 

1 

1 

1 

5 

4 

1 

1 

1 

1 

1 

1 

6 

5 

1 

1 

1 

1 

1 

1 

1 

7 

6 

1 

1 

1 

1 

4 

7 

1 

1 

1 

1 

1 

5 

8 

1 

1 

1 

1 

1 

5 

9 

1 

1 

1 

1 

1 

1 

6 

10 

1 

1 

1 

1 

1 

1 

6 

Total  errors 

10 

10 

9 

6 

5 

6 

3 

4 

1 

1 

0 

0 0 

55 

% Error... 

100  100 

90 

60 

50 

60 

30 

40 

10 

10 

0 

0 0 

% Accuracy 

0 

0 

10 

40 

50 

40 

70 

60 

90 

90 

100 

100  100 

Av.  time... 

— 

— 

5.8  4.1  2.9  2.5  2.3  2.7  2.0 

1.8 

1.9 

1.8  1.5 

Days 1 

Trials  

1 1 


TABLE  6 

Learning  Records  on  Box  6 
Dog  2 (Blind  $ ) 

Problem  3 

5 6 7 8 9 10  11  12  13  14  15  16 


1 1 1 


1 1 


^Total 

-[errors 

11 

9 

8 

9 

10 

8 

7 

9 


Total  errors  16  20  16  19  16  16  16  9 12  16  7 3 2 0 0 0 

% Error...  80  100  80  95  80  80  80  45  60  80  35  15  10  0 0 0 

% Accuracy  20  0 20  5 20  20  20  55  40  20  65  85  90  100  100  100 

A v.  time...  ...  8.3  8.3  4.8  4.3  2.9  2.6  2.7  1.6  2.1  1.9  1.6  1.3  1.3  1.0  1.0 


70 


HARRY  MILES  JOHNSON 


TABLE  6 — Continued 
Learning  Records  on  Box  6 
Dog  5 (Normal  cJ') 
Problem  6 


Days 

1 

2 

3 

4 

5 

6 

7 

8 9 10 

Total 

errors 

1 

1 

1 

2 

2 

1 

1 

1 

3 

3 

1 

1 

2 

4 

1 

1 

1 

3 

5 

1 

1 

2 

6 

1 

1 

1 

1 

1 

5 

7 

1 

1 

1 

3 

8 

1 

1 

9 

1 

1 

1 

3 

10 

1 

1 

1 

3 

11 

1 

1 

12 

1 

1 

1 

1 

1 

5 

13 

0 

14 

0 

15 

1 

1 

1 

1 

4 

16 

1 

1 

1 

1 

4 

17 

1 

1 

2 

18 

1 

1 

1 

3 

19 

1 

1 

1 

1 

4 

20 

1 

1 

1 

3 

Total  errors 

10 

15 

9 

7 

6 

5 

2 

0 0 0 

54 

% Error... 

50 

75 

45 

35 

30 

25 

10 

0 0 0 

% Accuracy 

50 

25 

55 

65 

70 

75 

90  100  100  100 

Av.  time... 

2.4  1.8  1.6  1.3  1.2  1.2 

1.0  1.0  1.0 

Dog  6 (Normal  c?) 

Problem  3 

Days 

1 

2 

3 

4 

5 

6 

7 

8 9 10  11 

Total 

errors 

1 

1 

1 

1 

1 

1 

5 

2 

1 

1 

1 

1 

1 

1 

6 

3 

1 

1 

1 

3 

4 

1 

1 

1 

1 

1 

5 

5 

1 

1 

1 

1 

1 

5 

6 

1 

1 

1 

1 

4 

7 

1 

1 

1 

3 

8 

1 

1 

1 

1 

1 

1 

6 

9 

1 

1 

1 

1 

4 

10 

1 

1 

1 

1 

4 

Total  errors 

10 

10 

7 

6 

6 

2 

3 

10  0 0 

45 

% Error... 

100 

100 

70 

60 

60 

20 

30 

10  0 0 0 

% Accuracy 

0 

0 

30 

40 

40 

80 

70 

90  100  100  100 

Av.  time.. 

.4.51.9  2.2  1.7  2.0  1.1 

1.3  1.0  1.5  1.0  1.0 

Dog  7 (Blind  cT) 

Problem  3 

Days 

1 

2 

3 

4 

5 

6 

7 

8 9 10  11 

Total 

Ti'i  o la 

1 nais 

i 

1 

1 

1 

1 

4 

2 

1 

1 

1 

1 

4 

3 

1 

1 

1 

3 

4 

1 

1 

1 

1 

1 

1 

6 

5 

1 

1 

1 

3 

6 

1 

1 

1 

1 

1 

l 

6 

7 

1 

1 

1 

1 

4 

8 

1 

1 

1 

3 

9 

1 

1 

2 

10 

1 

1 

1 

1 

4 

Total  errors 

7 

5 

8 

8 

6 

2 

2 

10  0 0 

39 

% Error... 

70 

50 

80 

80 

60 

20 

20 

10  0 0 0 

% Accuracy 

30 

50 

20 

20 

40 

80 

80 

90  100  100  100 

Av.ltime... 

6.5 

1.4  5.1  3.6  1.5  1,2  1.1 

1.0  1.0  1.0  1.0 

HABIT  FORMATION  IN  THE  DOG 


71 


TABLE  6 — Continued 
Learning  Records  on  Box  6 
Dog  8 (Blind  cT  , After  Operation) 
Problem  6 


Days 1 2 3 4 5 6 7 8 9 10  11  12 

Trials — — 

1 111111 

2 111  1 

3 1111  1 

4 11111 

5 1111  1 

6 11111 

7 11111  1 

8 1111  1 

9 1 1 

10  111  1 


Total  errors  9 10  786231  1000 

% Error...  90  100  70  80  60  20  30  10  10  0 0 0 

% Accuracy  10  0 30  20  40  80  70  90  90  100  100  100 

Av.  time... 3.2  3.1  2.1  2.3  1.7  1.9  1.4  1.2  1.0  1.1 


Total 

errors 

6 

4 

5 
5 
5 

5 

6 
5 
2 
4 


47 


Dogs  i and  2 were  operated  on,  25  March,  1911,  by  Dr.  Walter 
E.  Dandy,  of  the  Johns  Hopkins  Hospital.  The  operation  was 
quite  successful  and  healing  followed  without  a trace  of  infec- 
tion, but  the  corneas  were  found  in  bad  condition.  About 
three  weeks  after  the  operation  Dog  2 received  a scratch  on 
the  right  cornea  during  a fight.  This  wound  became  infected 
and  an  abscess  near  the  iris  followed.  So  far  as  gross  behavior 
indicated  the  animal  was  blind.  Some  tests  were  made  on  Dog 
1 to  discover  whether  the  eyes  were  functioning.  (Her  corneas 
were  not  as  clouded  in  appearance  as  were  those  of  Dog  2 ; 
the  pupils  reacted  well  to  light  and  she  seemed  in  better  general 
condition.) 

Following  the  operation  the  dogs  had  been  kept  in  a dark- 
room for  ten  days,  until  the  wounds  had  entirely  healed.  Dog 
1 was  then  taken  into  the  laboratory  and  subjected  to  a few 
rough  tests  of  the  presence  of  vision.  The  experimenter  stood 
at  one  end  of  a room  forty  feet  long,  holding  food  in  his  hand. 
The  animal  was  held  by  another  person  at  the  opposite  end 
of  the  room.  When  the  experimenter  called,  the  animal  was 
released  and  came  quickly  to  the  experimenter  for  food.  This 
was  repeated  four  or  five  t’mes.  Then  a white  pine  board,  .two 
feet  wide  and  eight  feet  long  was  set  on  edge  and  supported 
by  props  placed  against  the  side  away  from  the  animal.  When 
the  dog  was  called  she  ran  directly  into  the  board.  The  posi- 
tion of  the  latter  was  changed  four  or  five  times  but  with  no 
effect.  A rope  was  then  stretched  across  the  room.  The  animal 
tripped  over  it  each  time,  but  after  the  fourth  or  fifth  trial  began 


72 


HARRY  MILES  JOHNSON 


to  hesitate  when  she  approached  the  region  where  she  had 
tripped  before.  Twice  she  jumped  when  she  passed  near  where 
the  rope  had  been  stretched  at  the  previous  trial.  The  experi- 
ment was  not  continued  further  at  that  time,  as  prolongation 
of  the  tests  seemed  to  be  mere  cruelty. 

The  same  test  was  now  given  to  Dog  5,  the  normal  male. 
He  always  ran  around  or  jumped  over  the  board.  The  first 

trial  given  after  the  rope  was  stretched  he  tripped  over  the 

rope,  turning  a complete  half -somersault.  In  subsequent  trials 
he  always  jumped.  The  rope  was  held  in  the  same  place  for 
three  successive  trials  and  then  removed.  In  the  next  three 
successive  trials  when  the  animal  reached  the  place  where  the 
rope  had  been  stretched  he  jumped  as  he  had  jumped  when  the 

rope  was  there.  ' The  rope  was  then  stretched  again,  two  feet 

nearer  the  animal.  This  time  the  dog  tripped  by  jumping  too 
late — i.e.,  he  jumped  at  about  the  same  place  as  in  the  pre- 
vious trials.  In  subsequent  trials  he  always  adjusted  himself 
correctly. 

The  same  tests  were  repeated  on  Dog  1 a week  later.  She 
avoided  the  board  from  the  first,  by  means  of  what  sense- 
avenues  we  of  course  do  not  know.  She  never  succeeded  in 
adjusting  herself  to  the  rope,  however,  always  jumping  too 
late  or  too  soon. 

These  crude  tests  are  further  indication  of  the  slight  use  of 
vision  by  the  normal  dog,  and  made  it  seem  improbable  that 
Dogs  1 and  2 would  change  their  mode  of  attack  on  the  prob- 
lem-boxes because  of  the  little  vision  they  seemed  to  have. 
Accordingly  it  was  decided  to  discontinue  this  work  on  them. 
It  seemed  questionable,  however,  whether  better  results  might 
not  be  obtained  by  using  animals  which  had  not  been  kept  in 
the  blind  state  as  long  as  had  these.  This  was  the  reason  for 
having  the  same  operation  performed  on  Dogs  7 and  8.  I wish 
to  say  in  this  connection  that  our  experience  has  not  shown 
this  operation  useful  for  this  work.  It  is  not  in  itself  cruel, 
and  the  only  serious  inconvenience  which  the  blind  puppies 
showed  was  their  inability  to  compete  with  the  normal  puppies 
during  the  nursing  period.  The  normal  puppies  would  follow 
the  mother  into  places  in  the  animal’s  yard  where  the  blind 
puppies  would  not  go,  and  would  often  nurse  when  the  blind 
puppies  were  not  even  present.  After  weaning,  Dog  7 and 


HABIT  FORMATION  IN  THE  DOG 


73 


another  blind  litter  brother  not  used  in  these  experiments 
actually  outgrew  all  the  other  members  of  the  litter  of  seven. 
Dog  8,  which  was  smaller  at  birth  thrived  well,  while  another 
blind  male  of  the  same  litter,  which  was  rather  weakly  from 
the  beginning,  died  at  four  months  of  indigestion.  There  is 
no  reason  why  a puppy  which  has  undergone  this  operation 
should  not  live  as  thriftily  and  happily  as  a normal  puppy  if 
given  proper  care.  But  in  clipping  away  enough  of  the  edges 
of  the  eyelids  to  insure  the  formation  of  strong  scar  tissue  some 
small  glands  are  necessarily  destroyed.  While  the  dog  is  kept 
blinded,  too,  the  small  drain  which  is  left  at  the  corner  of  the 
eye  is  likely  to  become  clogged  and  a slight  infection  may 
develop  sufficiently  to  injure  the  cornea.  The  apparatus  of 
accommodation  may  atrophy  for  want  of  use.  A histological 
examination  of  the  optic  tracts  of  Dogs  i and  2 will  be  made 
at  some  time  in  the  future,  in  order  to  determine  whether  there 
was  deterioration  there. 

Dogs  7 and  8 were  operated  on,  30  May,  1912,  by  Dr.  Conrad 
Jacobson  of  the  Johns  Hopkins  Hospital.  Recovery  was  un- 
eventful. The  right  cornea  of  Dog  8 was  found  considerably 
clouded,  but  cleared  up  to  some  degree  in  about  two  weeks 
after  the  operation.  Dog  7 was  apparently  in  good  condition, 
although  it  was  difficult  to  detect  any  change  n his  behavior. 
Substantially  the  same  test  was  performed  on  him  and  Dog 
8 as  was  made  on  Dog  1.  There  were  no  other  persons  present, 
so  the  obstruction,  a board  two  feet  wide  and  seven  feet  long, 
covered  with  white  cheesecloth  was  placed  directly  in  his  habitual 
path  from  one  room  to  another.  Its  position  was  changed  after 
each  trial.  The  door  was  opened  by  a weight -and-pulley  sys- 
tem, and  the  operator  released  it  just  before  calling  the  dog. 
Dog  8 collided  once  with  the  board,  avoided  it  the  next  two 
consecutive  times,  collided  the  third  and  afterwards  came  into 
the  room  crouching  and  keeping  to  the  wall.  Dog  7 never 
bumped  into  the  board.  These  tests  were  made  fourteen  days 
after  the  operation.  Dog  8 avoided  the  board  successfully  in 
each  of  ten  trials  on  the  twenty-first  day  after  the  operation. 
In  their  other  behavior  absolutely  no  other  change  could  be 
noted.  Both  of  them  in  the  blind  state  had  found  their  way 
about  the  laboratory  and  yard.  From  about  a month  before 
the  operation  the  animals  were  kept  in  a building  at  Home- 


74 


HARRY  MILES  JOHNSON 


wood  and  at  times  were  given  the  freedom  of  a lawn  covering 
several  acres  for  an  hour  or  more  at  a time.  On  16  April,  1912 
Dogs  7 and  8 while  blind  escaped  with  Dog  6,  a normal  male 
of  the  same  litter  and  chased  a half -grown  cat  together.  The 
latter  took  refuge  in  a corner  of  a porch  and  was  caught  and 
killed  by  Dog  7.  It  was  not  possible  in  the  time  left  to  the 
experimenter  to  make  a test  of  the  vision  of  Dog  7,  the  animal 
which  after  the  operation  seemed  most  nearly  normal.  It  can- 
not be  ventured  how  much  or  how  little  vision  either  of  these 
animals  had.  Inasmuch  as  their  records  while  blind  compare 
very  favorably  with  that  of  the  normal  dogs  I have  only  nega- 
tive and  nconclusive  evidence  to  offer  on  the  question  which 
was  the  primary  object  of  this  investigation.  What  data  I 
have  gathered  seem  to  show  only  this  positive  fact:  that  the 
dog  is  capable  of  learning  to  make  complicated  adjustments 
and  of  performing  a surprising  number  of  “instinctive ” reac- 
tions perfectly  without  the  aid  of  vision.  This  fact  remains 
established  no  matter  what  later  tests  may  show  regarding  the 
dog’s  ability  to  make  visual  discriminations. 

RETENTION 

Sixty  days  after  the  third  problem  had  been  learned  by  each 
dog,  a test  was  made  of  the  retention  of  the  learning  of  the 
first  three  boxes.  The  results  are  not  shown  because  there  was 
absolutely  no  significant  variation  among  the  records  of  the 
different  animals.  None  showed  a loss  of  accuracy  of  over  10% 
on  the  first  day’s  work  in  the  retention  test,  and  in  only  one 
case  was  over  three  days’  work  necessary  to  regain  the  loss. 
This  exception  was  Dog  2 on  box  1.  In  learning  the  problem 
the  an’mal  had  used  first  her  paw,  then  her  nose,  to  depress  the 
latch.  She  settled  on  the  nose -method.  In  the  retention-tests 
the  paw-method  reappeared  and  persisted  for  six  days  before 
the  nose-method  was  completely  re-establi?hed.  The  time  re- 
quired for  opening  the  box  by  either  method  was  about  the 
same — not  over  one  second. 

CONTROL  TESTS 

Two  control  tests  were  made  on  Dogs  1,  2 and  5.  The  first 
was  for  the  purpose  of  observing  what  disturbance  resulted  from 
requiring  the  dogs  to  perform  their  work  in  total  darkness.  Two 


HABIT  FORMATION  IN  THE  DOG 


75 


boxes,  which  the  animals  had  learned  and  were  then  opening  in 
one  second  or  less,  were  provided  with  contacts  of  brass.  When 
the  door  of  the  box  was  closed,  a circuit  was  formed,  the  cur- 
rent running  from  the  positive  pole  of  a dry  battery  through 
the  magnet  of  a Schallhammer  in  the  experimentor’s  room,  to 
the  metal  contacts  on  the  door  and  jamb  of  the  box,  to  the 
negative  pole  of  the  battery.  When  the  latch  of  the  door  was 
released  this  circuit  was  broken  and  the  hammer  being  drawrn 
from  the  magnet  by  a spring  gave  a signal-click.  The  animal- 
room  was  darkened  by  heavy  black  tar-paper  nailed  over  the 
windows  and  openings  about  the  door.  The  tests  were  made 
at  night  and  all  lights  in  the  animal-room  and  the  room  ad- 
joining were  put  out  before  the  animal  was  admitted  to  the 
experiment-room.  Time  was  taken  from  the  animal’s  passing 
between  the  glass  door  and  the  food-box,  and  the  click  of  the 
Schallhammer  when  the  box  was  opened.  This  is  accurate  to 
within  one-half  second.  The  blind  dogs  were  slightly  disturbed, 
as  is  shown  by  the  fact  that  the  time  of  their  first  ten  reactions 
varied  between  four  and  seven  seconds;  the  next  ten  averaged 
about  two.  Dog  5,  normal,  was  much  more  disturbed.  His 
first  reaction  under  the  changed  conditions  required  thirteen 
seconds  and  there  were  many  useless  movements.  Several 
times  in  the  first  six  trials  he  climbed  on  top  of  the  box  and 
scratched  there.  The  reactions  after  the  sixth  were'  more  defi- 
nite, and  after  the  twelfth  there  were  no  more  errors,  and  the 
time  for  each  thereafter  averaged  1.3  seconds  for  thirty  trials. 
These  results  indicate  that  the  light  had  some  stimulating  effect, 
on  both  the  blind  and  the  normal  dogs. 

The  second  control  was  a test  on  Dogs  1,  2 and  5,  of  disturb- 
ance when  a box  previously  learned  by  the  dog  was  oriented 
in  another  direction.  As  the  boxes  stood  when  the  animals 
were  learning  them,  the  latch  was  always  at  the  northwest 
corner;  when  the  box  was  turned  90°,  then  the  latch  was  on 
the  northeast  corner,  etc.  The  following'  table  summarizes  the 
disturbance  which  follows: 


76 


HARRY  MILES  JOHNSON 


TABLE  7 

Disturbance  Following  Rotation  of  Problem  Box  Already  Learned 


Dog  1. 

Blind  $ . 

Box  4 

Position  of  latch- 

Day 

No. 

% 

Av.  time 

corner  of  box 

trials 

Accuracy 

seconds 

N.W  . 

1 

10 

100 

2.2 

N.  E. 

1 

10 

40 

— 

U 

2 

20 

80 

2.6 

a 

3 

10 

100 

3.2 

S.  E. 

3 

10 

20 

3.4 

4 

20 

60 

3.0 

U 

5 

20 

100 

2.9 

u 

6 

10 

100 

3.0 

s.  w. 

6 

10 

00 

5.8 

a 

7 

20 

40 

3.6 

“ 

8 

20 

80 

7.3 

u 

9 

20 

. 90 

4.2 

“ 

10 

20 

100 

3.0 

Dog  2. 

Blind  $ . 

Box  1 

Position  of  latch- 

No. 

% 

Av.  time 

corner  of  box 

Day 

trials 

Accuracy 

seconds 

N.  W. 

1 

10 

100 

1.1 

N.  E. 

1 

10 

00 

11.0 

“ 

2 

20 

70 

4.1 

U 

3 

20 

95 

2.0 

S.  E. 

4 

20 

00 

6.9 

(C 

5 

20 

90 

3.5 

u 

6 

20 

95 

2.5 

a 

7 

10 

100 

2.2 

s.  w. 

7 

10 

50 

2.0 

8 

20 

70 

3.0 

u 

9 

20 

100 

2.0 

Dog  5.  Normal  cJ1. 

Box  1 

Position  of  latch- 

No. 

% 

Av.  time 

corner  of  box 

Day 

trials 

Accuracy 

seconds 

N.  W. 

1 

10 

100 

1.0  ‘ 

N.  E. 

1 

10 

60 

9.1 

U 

2 

20 

90 

1.0 

a 

3 

10 

100 

1.0 

S.  E. 

3 

10 

90 

2.0 

u 

4 

20 

95 

2.5 

a 

5 

10 

100 

2.0 

s.  w. 

5 

10 

50 

2.6 

u 

6 

20 

80 

2.0 

u 

7 

20 

100 

2.0 

The  animals’  behavior  in  this  new  situation  is  interesting. 
The  turning  of  the  box  90  ° made  the  problem  practically  a 
new  one  for  each  dog.  Every  animal  attacked  the  box  at  the 
northwest  corner,  as  if  the  latch  were  still  there.  After  the 
usual  methods  of  “nosing,”  scratching  and  biting  had  failed, 
the  animals  resorted  to  violent  random  movements,  scratching 


HABIT  FORMATION  IN  THE  DOG 


77 


over  the  north  side  of  the  box,  walking  around  it,  barking  all 
the  while.  Dog  i required  several  hours  for  opening  the  box 
the  first  time.  A period  of  work,  which  never  lasted  over  ninety 
seconds,  and  which  averaged  near  fifteen,  would  be  followed 
by  a prolonged  rest.  This  is  characteristic  of  all  my  animals’ 
reaction  to  a new  box.  After  an  animal  had  opened  the  box 
once  or  twice  in  the  new  position,  the  time  necessary  for  open- 
ing was  quickly  shortened  and  the  principal  errors  made  there- 
after were  those  of  hesitation  or  attack  at  the  northwest  corner. 

Dog  5 surprised  the  members  of  the  laboratory  who  ven- 
tured to  predict  his  behavior  when  the  box  was  first  turned 
90°  The  writer  expected  him  to  “hunt  for  the  latch.”  He 
showed  fully  as  much  disturbance  as  either  blind  dog.  When 
first  admitted  to  the  experiment  room  he  went  directly  to  the 
northwest  corner,  scratched  violently  at  the  wire  over  the  whole 
north  side,  dragged  the  box,  which  was  heavily  weighted,  some 
five  inches  with  his  teeth,  climbed  on  top  of  the  box,  then  lay 
down  to  rest  after  eighty-five  seconds  of  work.  He  opened 
the  box  at  the  second  attack,  after  accidentally  touching  the 
latch  with  his  head.  I wish  to  stress  one  feature  of  his  beha- 
vior. Several  times  during  his  periods  of  effort  his  head  and 
nose  came  within  an  inch  of  the  projecting  (lift)  latch  bar.  His 
actions  were  not  affected  in  the  least  by  proximity  to  the  latch 
until  he  actually  touched  the  latch.  Then,  in  less  time  than  is 
necessary  for  working  a stop-watch  lever,  he  or  ented  himself 
to  the  latch  and  opened  the  door  by  a single  movement. 

Much  less  disturbance  was  shown  when  the  box  was  turned 
another  90  °.  The  animals  went  to  the  southeast  corner  after 
only  a few  seconds  of  effort  at  the  northeast  corner.  At  this 
point  the  first  difference  in  method  appeared.  Dogs  2 and  3 
never  changed  their  customary  pathway.  They  continued  to 
pass  to  the  southeast  corner  by  way  of  the  northwest  and  north- 
east corners.  Dog  5 went  directly  to  the  southeast  corner  after 
the  seventh  trial. 

When  the  box  was  turned  another  90 0 farther,  making  the 
latch  corner  southwest,  Dog  5 went  first  to  the  southeast  corner 
and  paused  long  enough  to  give  only  one  scratch,  then  hastened 
to  the  southwest  corner,  to  which  in  subsequent  trials  he  went 
directly.  His  errors  were  those  of  passing  too  far  to  the  north 
before  orienting  himself  to  the  latch,  and,  attacking  the  latch 


1 


78 


HARRY  MILES  JOHNSON 


too  far  from  the  free  end  to  open  the  box  with  one  effort.  The 
blind  dogs  at  the  first  trial  passed  around  the  box,  stopping  to 
scratch  at  the  southeast  end,  and  then  trying  the  southeast 
and  northeast  corners  before  attacking  the  latch  at  the  south- 
west. Both  learned  to  stop  at  the  southwest  corner  during  the 
first  series  of  ten  trials:  Dog  i at  the  third  and  Dog  2 at  the 
eighth  trial. 


SUMMARY 

The  above  experiments  have  shown  that  it  is  impracticable 
to  attack  the  “Molyneux  problem”  by  using  dogs  rendered 
temporarily  blind  by  this  operation. 

It  is  evident  from  the  records  that  vision  is  not  necessary  to 
enable  the  dog  to  make  quite  complicated  adjustments.  The 
behavior  of  my  animals,  particularly  that  of  Dog  5 in  the  con- 
trol tests  indicates  that  the  dog  may  make  little  use  of  vision. 
His  reaction  to  the  rope  and  to  the  disoriented  box  strengthens 
the  belief  that  the  normal  as  well  as  the  blind  dogs,  in  ordinary 
situations  rely  greatly  on  kinaesthetic  and  muscular  sense- 
processes  in  making  their  adjustments.  This  accords  with  the 
data  accumulated  by  Watson,  Richardson  and  Vincent  in  the  rat. 

The  rate  and  methods  of  learning  in  blind  and  normal  dogs 
shows  surprisingly  little  difference. 

Dogs  given  only  ten  trials  a day  required  fewer  trials  for 
learning,  on  the  average,  than  those  given  twenty  trials.  This 
fact  suggests  the  question,  what  is  the  optimal  number  of  daily 
trials  to  educe  perfect  habits  with  the  least  effort? 


VITA 

I was  born  16  May,  1885  at  Ridge  Prairie,  Saline  County, 
Missouri,  my  parents  being  Daniel  H.  and  Virginia  (Reeder) 
Johnson.  My  primary  education  was  received  at  home  and  in 
the  public  schools;  secondary  training  in  the  Nelson  (Missouri) 
high  school,  from  which  I was  graduated  in  1900.  Following 
this  I spent  five  years  in  commercial  work  and  railway  (con- 
struction) engineering.  I was  a student  in  Missouri  Valley 
College  in  1905-09,  being  admitted  to  the  degree  of  Bachelor 
of  Arts,  magna  cum  laude,  in  1909.  From  the  year  1909-10  to 
June,  1912,  I was  a graduate  student  in  the  Johns  Hopkins 
University  in  psychology,  physiology  and  neurology,  with  some 
additional  work  in  philosophy.  I was  engaged  in  research  work 
in  the  University  of  Chicago  during  the  summer  of  1911.  I was 
appointed  a fellow  of  the  Johns  Hopkins  University  in  June,  1 91 1 . 

The  work  in  the  Johns  Hopkins  University  was  done  under 
Professors  Watson,  Dunlap,  Meyer,  Jennings,  Howell,  Snyder, 
Mall,  Sabin,  Griffin,  Lovejoy  and  Buchner,  and  Doctor  Furry; 
that  in  the  University  of  Chicago,  under  Professors  Angell, 
C.  Judson  Herrick,  and  Clark. 


79 


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